The Skinning Primer
A comprehensive look at Windows customization
2006 Edition
by Brad Wardell
Don't be a drone. Don't let your desktop look like this!
Be an individual! Make your desktop YOUR desktop!
Disclaimer: I work at Stardock. I'm a guy who is so into messing around with the OS that I made it a large part of my career. But since I work at a company that makes this stuff, I obviously have my own biases and such. I've written this as objectively as I can.
Terminology -- what the heck is a "skin"?
Skins, themes, suites, styles, oh my! What is all this stuff? Let's agree on some termilogy...
Skin. A skin is a collection of graphics designed to replace the default user interface graphics of a program. That means its push buttons, title bars, scrollbars, radio buttons, check boxes, etc. Skins that are explicitly designed to change the actual OS's user interface are called visual styles.
Theme. A theme is a set of elements designed to change aspects of your desktop. It is often used to describe skins as well. A theme typically corresponds with a single program.
Suite. A suite is a full set of skins and themes used to change your entire desktop. A suite may rely on skins and themes from a variety of different programs in order to achieve the desired effect. For instance, a suite might include a skin to change your Windows GUI, a wallpaper, and an icon package.
What about the types of software?
Skins, themes and suites are content. They are the stuff -- the artwork -- that is applied to change the system. But something has to change it. This article will talk about several different types including:
- GUI Changers. These are programs that change the look & feel of the operating system's graphical user interface.
- Desktop Extenders. These are programs that add bits and pieces to your existing desktop that let you customize how it looks and functions.
- The Super Desktop Extenders. These are programs that totally remake the way your existing desktop looks and functions.
- The Shell Replacements. These are programs that simply replace the entire Windows shell with their own.
- Icons. Gotta talk about things that change, create, and enhance those pretty little pictures on your desktop.
- Instant Messengers. Customizing and customizable instant messaging.
- Media Players. Skinnable media players!
Once upon a time some user, some where, noticed that their computer looked exactly like everyone else's computer. And that just didn't make sense to them. After all, everything else is personalized based on the individual needs and tastes of the consumer -- cars, phones, shoes, appliances, houses, etc. Yet computers, in which people spend so much time in front of, looked exactly the same.
This user started looking at what they could do on their computer to change it to be more their own. They changed the background of their desktop (called a wallpaper). And then they tried to change their icons and found they could change a few of them but not most of them. Then they tried to change the color of their title bars. Then they tried to change the way their Start bar worked and what it looked like and found they couldn't really do that.
This user wasn't alone. There were thousands like him. People of all ages from around the world had the same desires and no way to address them. But nature abhors a vacuum and pretty soon the pieces started coming together.
A new company called Nullsoft made a program called Winamp. Winamp wasn't the first program to play music files called MP3s. What made it special was that users could change the way it looked by applying a new graphical interface called a "skin". Across the country, some guys in Michigan were trying to make a Windows version of their popular desktop enhancement suite that they had made on OS/2 called Object Desktop. And they were finding that Windows was a lot harder to customize than OS/2 was. And so the call went out and this company, called Stardock (where I work), began bringing together the "best and brightest" developers to tackle the problem. Pretty soon a program was made that could change the actual graphical user interface of Windows and it was called WindowBlinds.
Of course, neat software on its own, even with cool capabilities means nothing if there's no place for users to get these "skins". Two websites were started around the same time. One was called Customize.org and the other one Skinz.org. They let users download skins and wallpapers for these apps. These websites also helped encourage other developers who had their own ideas on what to create to help customize Microsoft Windows. Some people wanted to replace the actual shell (the desktop itself) with their own. The first popular one was called Litestep. Another company wanted to replace the desktop menu with their own, this came to be called NextStart. And Stardock added a program that could change all the icons on Windows and it was called IconPackager. Soon after it added a program that could put interesting objects on the desktop that could give information, provide simple functionality, and looked really cool and it was called DesktopX.
By 2000, the basics of the skinning world were set. Other programs were made that would compete with the above programs. New programs were made to support new ideas others had. And in 2001, Microsoft itself started really getting into skinning in its own right with a skinnable Windows Media Player and a new version of Windows that was much easier to skin called Windows XP.
Icons
Next to changing your wallpaper, one of the most obvious things to change would be your icons. Icons are the little pictures on your desktop that represent things. How do we change them? How do we make them? Here's how!
IconPackager
Here's the deal -- on Windows you can change some of your icons -- but not most of them. And even if you could change all your icons, it would be a pain in the butt to try to change them all individually.
Back in 1997, Stardock released a Windows equivalent of a program they had made on OS/2 a few years before -- IconPackager. IconPackager lets users change all their icons by applying "packages" of icons. It enables users to change virtually every icon on Windows. And once a user changes all their icons, they can package it all up and share with others so that others won't have to sit there and change every icon individually. A truly complete icon package might have 150 icons in them!
IconPackager has continued to be regularly updated to support changing more and more icons and even works on Windows Vista.
Microangelo Creation
Replacing your icons is great but what if you want to actually make your own icons?
That's where Microangelo Creation comes into play. It's a graphics design tool unto itself. You can do everything you need in order to create icons. It includes full-blown editing.
IconWorkshop
In all fairness you have to also include Axialis Software's IconWorkshop. Like Microangelo's Creation, it's a full blown graphics design package as well.
Simply put, IconWorkshop is a one-stop shop for icon creation.
IconDeveloper
IconDeveloper takes a totally different strategy towards icon creation than IconWorkshop and Microangelo. It assumes that people will create their artwork in professional design programs like Photoshop, Illustrator, Corel Draw, etc. and then want to turn them into icons at that point.
As a result, IconDeveloper simply takes your artwork in nearly any format and then turns that into an icon. It automatically generates all the common icon formats for the user and has some very sophisticated algorithms to make sure that the icon looks good at any size. It even supports batch converts so users can take an entire directory of images and quickly turn them into icons.
IconX
IconX doesn't create icons. It doesn't apply icons. It makes your existing desktop icons..better. Common problem -- you have really fancy icons that you want to have be nice and big on your desktop but not huge everywhere else. No problem, IconX can do this and much more. IconX can put shadows under your icons, make them react to mouse-over events (like grow in size when you put your mouse over the icon). It can also enhance your icon labels.
Windows Vista will likely be very good news for IconX since icons in Windows Vista are natively 256x256 which means that users are going to want to make use of those icons on their desktop more than ever. The mouse-over events and enhanced labels are a simple way to beautify your desktop. Simply turn on IconX and your desktop icons will look even better.
Skinning the Windows GUI
After having changed your wallpaper and changed your icons, one of the next things you'd likely look at is the actual Windows graphical user interface (GUI). The Windows GUI can be described as being the title bar, borders of a window, buttons, dialogs, Start bar, and other controls found in Windows. How do we change the way those look and feel? What if I want to make Windows look like another OS? What if you wanted to make Windows look like a Mac?
On Windows 98, ME, NT, and 2000, the OS wasn't natively skinnable. It wasn't designed to have its user interface altered by anyone. This is particularly true of Windows 98 and ME which are not well suited for customization because of their GDI limit (Windows 98 and Windows ME only support having 128K --Kilobytes-- of memory used for GUI related graphics, if this memory is used up, the system can become unstable). But Windows XP supported skinning natively which enabled programs to change the way it looked much more completely and reliably.
Users install the program WindowBlinds onto Windows XP, Windows ME, Windows 98, or Windows 2000 and it extends the existing skinning features (in the case of Windows XP) or provides the complete skinning engine (in the case of other versions of Windows).
The most popular way to skin the Windows GUI is using the program WindowBlinds. It runs on Windows Vista, XP, 2000, ME, and 98. It applies what are called "visual styles". A visual style being a skin designed specifically to change the actual OS user interface. WindowBlinds has been around a long time and earlier versions of it were mostly used on Windows 98
The visual styles (skins) created are made by individual authors usually using a skin editor such as SkinStudio (www.skinstudio.net). SkinStudio allows skinners to make visual styles without the pain that used to be involved in creating a nice skin. The finished skins are then uploaded to websites that allow others to enjoy the hard work by the skin author.
WindowBlinds's is flexible enough that people can create skins for it that make Windows look like other operating systems too.
With the release of Windows XP, Stardock and Microsoft worked together to make skinning more seamless. Microsoft provided new APIs in Windows XP that can accelerate skinning. Stardock also worked with nVidia and ATI so that WindowBlinds could take advantage of hardware acceleration on those video cards. The result is WindowBlinds visual styles are hardware accelerated.
WindowBlinds on XP lets XP's visual style engine use WindowBlinds visual styles
WindowBlinds was the first program to let users change the Windows GUI completely. But it's not the only way to do it. If you're feeling pretty technical, you can patch the system file uxtheme.dll and then apply patched versions of luna.msstyles that change the images inside along with some of the metrics. While not as flexible or powerful as WindowBlinds, it has the advantage of being free. Some companies have made programs that patch these same files in memory but charge money for it. They aren't actually providing a skinning engine, they're simply patching the digital signature verification that prevents users from messing with the msstyles files. My view is that there's nothing wrong with patching your uxtheme file, but don't pay money to do it.
The Desktop Extenders
Where the GUI changing programs like WindowBlinds customize the look and feel of your existing Windows interface, desktop extenders are designed to add new functionality to them. They don't so much replace what you already have but rather extend what they can do.
DesktopX
The first popular desktop extender on Windows was called DesktopX. Released in 2000, DesktopX enables users to literally build their own desktop. Users can create entire desktops and export them as .desktop files, export parts of their desktop as widgets, or export individual objects as objects.
DesktopX widgets in action
DesktopX objects in action
DesktopX .desktops in action
While DesktopX can do these 3 things, there are programs that specialize on individual parts...
DesktopX also comes in a Pro version that allows the creation of gadgets. Gadgets are the same as widgets except they don't require the user to download and install the creation program. That is, gadgets are stand-alone programs. The main downside of widgets is that if you see a cool widget that may only be 300k, you first have to download the 9 megabyte parent program (DesktopX, Konfabulator, etc.). Gadgets don't have this issue.
Konfabulator
Konfabuator aka Yahoo Widgets (widgets.yahoo.com) specializes on creating widgets. And it does it very well. Originally released on the Macintosh in 2003, the program became popular thanks to being cross-platform and a little help from the Macintosh community. Its popularity on the Mac was enough that Apple incorporated a similar feature into MacOS X Tiger. In 2005, the program and in fact the company that makes it was acquired by Yahoo.
Typical widgets include clocks, system resource monitors, RSS feeds, weather monitors, stock tickers, and widgets that display information gathered from the Internet. They have gathered a very loyal following over the past couple of years.
Kapsules
Kapsules (http://www.widgetforge.com/) is very similar to Konfabulator except that rather than relying solely on Javascript for creating widgets, it is a .NET based program which means users can create their widgets using any .NET supported language.
SysMetrix
Whereas DesktopX widgets and Konfabulator widgets are totally free form, SysMetrix specializes on very specific types of widgets. SysMetrix focuses on displaying system resources and other specific bits of information. You wouldn't, for instance, make a game with SysMetrix or an MP3 player. It displays info and it does it very well.
Samurize
In a similar vein to SysMetrix, there is Samurize. Samurize is the result of developers who have access to a time machine. The developers went ahead to the year 2008, saw how visual-oriented software is made, and then returned back to the year 2002 and developed it. In the future, a lot of software will be created using Microsoft's Sparkle. Samurize is basically Sparkle -- today in many respects. Users build their desktop using an advanced editor. When the user is done creating their widget or their desktop, they can export them.
In many respects, Samurize is similar to DesktopX. The main difference is in packaging and how content is created. DesktopX users create their stuff on their desktop. Samurize users create their stuff using the included Samurize editor. The Samurize editor is so similar to Microsoft's Sparkle that one must wonder if Microsoft saw Samurize (to be fair to Sparkle, it supports 3D but to be fair to Samurize, live 3D isn't really possible on XP).
Making Samurize desktops/widgets is done using a sophisticated editor
Final creation exported out for end users.
Samurize doesn't have the following that the other programs have. But that's not its fault. It's an issue of marketing more than anything. There is also, of course, the intense competition in this area right now. But all these programs will have an opportunity to shake things up when Windows Vista shows up and the playing field is re-leveled.
Avedesk
Avedesk doesn't quite do widgets but its content are more than simple desktop objects. Its author calls them Desklets which seems to be appropriate.
Desklets are sort of like super icons that users put on their desktop. DesktopX objects can do much the same but there's a key difference -- desklets are much easier for users to configure.
Here's the thing about widgets - you like that widget? Right? Looks great? Want to change it? TOUGH. Desklets don't suffer this limitation. The limitation on desklets is that you really don't create new desklets (you can but it's very difficult). Instead you customize the two dozen or so desklets that are already available to look and feel how you want them to. Deskets, IMO, are better than widgets. They are a better idea. The reason I say that is because in the final analysis, there's only about two dozen different types of widgets. You've got your calendar widget, your drive space widget, your weather widget, your stock ticker widget, your sticky note widget, your to-do list widget, and so forth. Widgets are open ended so on the surface they seem much more flexible than desklets since in theory you have no limit on the # of widgets you can create. But since the release of DesktopX back in 1999, we've only seen a few dozen different types of widgets ever made. There's thousands of widgets out there but most of them are derivative of other widgets (i.e. Konfabulator might have 2000 widgets but how many of them are clocks?).
So the reason I think Desklets are better boils down to the fact that it's easy for people to "skin" the different desklets to have different looks to them. By contrast, widgets can't really be skinned. If you want to make your own widget you can but it's a lot harder to create a widget than to simply skin an existing desklet.
The only thing really holding Avedesk back from massive popularity is that it doesn't really have a headquarters. It's one of the community apps on Aqua-Soft. It also doesn't have a lot of original artwork since it's being done on a shoe-string budget. Where DesktopX and Konfabulator can battle it out with their own staffs of graphics designers, Avedesk has to go with what the community provides. It's a testament, however, of how good an idea desklets are that it's as popular as it is despite having so much fewer resources backing it.
ObjectDock
ObjectDock started its life as a simple dock program for putting short-cuts and optionally displaying running tasks. It is similar in many respects to docks on other operating systems such as MacOS X but is designed for the Windows environment.
Over the years, it has continued to advance and is, by far, the most popular dock program. There are other dock programs out there such as the discontinued yZ Dock. Other programs exist as well but they all largely make use of content either made for ObjectDock or yZ Dock. ObjectDock is a free program that lets you throw on docklets (which are essentially the same as desklets), short-cuts, and running tasks. It's very simple to set up and use and very useful.
In 2004, Stardock released a Plus version of ObjectDock which added tabbed support.
ObjectDock tabs can be used to help organize your screen without it getting in the way:
See the tabs on the edges of the screen?
ObjectDock Plus can also display the system tray which is quite handy for those who want to hide their Start bar entirely and just use ObjectDock as their way of navigating through Windows. As pretty as ObjectDock and ObjectDock Plus are, they are probably some of the most useful of the enhancement programs out there.
The SUPER Extenders
Super Extenders is a word I made up. Just now. At this very second. I did in order to describe a class of desktop customization software that can be used to build your own desktop shell environment or be a shell on its own. They aren't..quite shells but they are designed to typically jettison most of the Windows explorer environment and use their own. The Super Extenders came out in the age before widgets and desklets and some of their thunder has been stolen by the latest generation of desktop extenders. That's because the desktop extenders are far more targeted.
As skinning has become more popular, the market for more specialized programs has been created and what we've seen so far is that the more specialized the program, the better it tends to do since it's focusing on one thing. The programs discussed below have had a harder time as a result since they try to do a lot of things that some specialist programs are better at. That isn't to say that these programs don't still have a following -- they do. It's just that their momentum isn't quite as much as it once was and as a result they haven't gotten quite the same level of updates as they used to.
ObjectBar
ObjectBar lets people do some major surgery on the Windows desktop if they so choose. Essentially, it lets people create their own Start bars. It provides all the functionality that one would ever need to create their own environment. It has features that are akin to what's available on Linux, MacOS X, and elsewhere and with it, users have created some neat stuff.
Unfortunately, ObjectBar 2 has been in development for years and still hasn't come out. Stardock keeps putting out new beta releases but it's still not quite ready for release at the time I'm writing this (it's getting close). ObjectBar 2 promises to bring some pretty neat features such as the ability to embed widgets into a bar and the ability for users to export their creations as their own programs (EXEs). That way, someone can make their own perfected Windows environment, export it, and send it to others to use.
ObjectBar 2 is Stardock's answer to the changing ecosystem of Windows customization. Rather than trying to be all things to all people, it has narrowed its focus to allow people to create fantastic specialized things and export them.
The idea behind ObjectBar 2 is to merge the benefits of desklets and widgets together. Users can export their creations as EXEs and users who use those creations can skin and customize them how they see fit. So one could imagine a little power bar that displays a calendar, local weather, drive info, most frequently used programs and a bunch of links to a website. Users can then easily skin it using ObjectBar skins or WindowBlinds skins into it and modify it as they see fit. Whether this strategy works out remains to be seen.
NeXTStart
NeXTStart has been around a long time. It has traditionally specialized in letting users create their own desktop menus. Over time, it has expanded to do more and more to the point that it and ObjectBar essentially are competitors with a touch of ObjectDock for good measure.
NeXTStart adds pop up and permanent menus to Windows. It can extend your existing shell or take it over.
NeXTStart 3 was originally released back in 2003 and 3.4 was released in late 2005. The latest versions can replace nearly every element of the Explorer environment.
Another program that seems to have been discontinued is Hoverdesk. In the age of DesktopX, AveDesk, Konfabulator, etc. the super extenders have had a tough time. They've had to evolve and that has involved a great deal of work. The super extenders are kind of stuck between the extenders and the full-blown shell replacements. But NextStart and ObjectBar pesevere.
Shells & Alternative Environments...
Okay, maybe you think that the Windows desktop is just too bad to even try to extend. Maybe it's time to throw it all out and start over. That's where alternative environments and shells can come in.
Here are some of the shells replacements and shell environments.
Litestep
Litestep is a freeware, open-source replacement shell for Windows. At one time, it was the defacto alternative shell. But in recent years, it has seen its popularity wane. This isn't so much the fault of Litestep as opposed to the reality that Windows XP is pretty solid and memory is no longer an issue. When Litestep was in its prime, the Windows shell was bloated and buggy and crash-prone. Now, it's still bloated but most people don't really notice anymore. Sure, Explorer may use 30 megs but with most people having systems with nearly a gigabyte or more of memory, it's not an issue.
Talisman
Talisman is a commercial shell replacement made in Russia. It has a lot of features built into it that allow people to create some pretty rich and specialized desktops.
Talisman's strategy has been to try to incorporate those key two dozen or so widget concepts into its base feature set and then allow users to create their own skinned shells that have those features. It's a solid idea IMO and Talisman's longevity tends to imply that it must be working decently enough.
Aston Shell
AstonShell is Talisman's competitor in every sense of the word. They have very similar strategies and which one is better depends on who you talk to. Like Talisman, Aston is a commercial program (i.e. it's not free). But for those who are really serious about completely revamping Windows, it's something to bear in mind.
Aston and Talisman also loosely compete against the super desktop extenders as well as the normal desktop extenders. One can almost imagine the path a new user would take:
First they would change their GUI and icons. Then they would try a desktop extender. Then they might get a super desktop extender and then eventually decide to toss out the entire shell and start with a fresh one such as Aston or Talisman.
According to Aston, there's 5 main reasons to use it: Speed, Reliability, Power, Beauty, and Flexibility. I don't personally think speed is that much of a consideration at this point for most people. Contrary to their website, most modern desktop enhancements don't slow down your computer. The days of Windows 98 are long gone for most people.
Much of the challenge for alternative shells is to justify themselves in a Windows XP world. With Windows Vista around the corner, which has a 3D composited desktop and new shell, it will be a challenge for these shells to evolve in that brave new world. What I like about Aston Shell is that it has focused on robustness over features. It hasn't fallen into the trap of "Hey, some user in Croatia says we should have a feature in which we can monitor the user's CPU temperature on Windows 64!" Instead they've focused on trying to provide a good out of the box experience that won't scare off novice users.
Mouse Cursors
CursorXP
CursorXP is designed to let Windows XP and Windows 2000 users to apply nicer cursors to their system. The advantage of CursorXP is that its cursors can be alpha blended, this means that they blend into whatever is behind them making them appear much smoother than the standard Windows cursors. The other advantage is that they can be of any size the user wishes (Windows cursors are locked into specific sizes). Combine this with fluid animation and you can get some really cool looking cursors. (www.cursorxp.com)
Media Players
WINAMP
WinAmp started it all. Not enough good things can be said about Nullsoft. They started it. WinAmp is an MP3 player that is skinnable. It is in its third generation. Skinning is good business. WinAmp wasn't the first MP3 player, but it was the first one that was skinnable. And that helped make it the most popular one which led to AOL purchasing Nullsoft for many millions of dollars. (www.winamp.com). Winamp has had a bit of a tough year. It went to version 3 with a lot of publicity and with almost equal publicity had to go back to the 2.x version. Which is a bit unfortunate because the technology behind Winamp 3 was incredible.
Winamp 5 though combines what was good about Winamp 3 and Winamp 2.
Windows Media Player
Microsoft saw how popular skinnable MP3 players was that they decided to make their media player. The good news is that Windows Media Player skins are very powerful and really pretty. The bad news is that they are really really hard to create. So there aren't very many of them.
Windows Media Player skin.
Logon Screens
Logon screens on Windows XP can be replaced in one of two ways -- you can literally patch the logonui.exe on your hard disk (either do it yourself or use a front end that replaces your logonui.exe with one you download). The other way is to use LogonStudio. Since the former way involves violating copyright laws, we'll focus on the latter.
LogonStudio (.LogonXP)
LogonStudio is a program that lets users apply new logon screens to their Windows XP systems. It can also edit and create new logons as well from a built in editor. (www.logonstudio.com). It is a free program and was largely created so that people could replace their logon screens with data files (.logonxp files) rather than trading warez (logonui.exe) back and forth.
The future of LogonStudio (and indeed all logon programs) is murky. Microsoft has told us that they are taking steps to make it very difficult if not impossible for third parties to customize the logon screen. For Microsoft, it's a branding issue. That isn't to say that it would be impossible to do change it, but the amount of effort involved may be much higher than today.
That said, Stardock is working on a LogonStudio 2 that it hopes will work for Windows Vista when the time comes:
LogonStudio 2
Instant Messengers
Trillian
Trillian is a skinnable instant messenger that supports most of the major instant messaging clients as well as having IRC built in. It's very popular (most of the people at work use it). It started out as purely freeware but as it has become more popular (and expenses started to mount) its developers have begun to offer a "Pro" version with additional features. Trillian is now the independent instant messenger to beat.
XFIRE
Xfire is a instant messenger designed specifically for games. It's skinnable and doesn't really have a skin site yet (WinCustomize.com plans to create a section).
Boot Screens
Boot screens have become pretty popular. I must admit as someone who only boots a few times per month, I don't see the appeal. But like I said, they are very popular with other people and so I cover them here.
The most popular program for doing this is called BootSkin. It's free and was created because people were changing their boot screens by patching their NTkernel (the Windows XP kernel file!). Just the thought that someone was patching their OS kernel to have a new boot screen sends shivers down my spine. The idea behind BootSkin was to change the boot screen safely.
Suites
A suite is a file that contains all of the above into a single file that can then be applied at once. It's very convenient but as you can imagine, suites can be pretty big in size.
Suites are applied by a program called Theme Manager:
Theme Manager comes in several forms. There's Theme Manager Free which simply acts as a front end to all the programs mentioned above. There's Theme Manager Plus which bundles WindowBlinds & IconPackager and applies specialized themes and there's Theme Manager OEM which is licensed by companies who want to deliver branded desktops to their customers (Microsoft, Nintendo, Alienware, NASCAR, and countless others have licensed Theme Manager OEM).
Here are some examples:
Companies such as Microsoft, Nintendo, Warner Bros., and many others have found that skinning is a powerful marketing / branding tool.
Websites that support customization
So you've got Windows XP and want to get some skins for it or you have Windows 98, ME or 2000 and want to start customizing. Where do you go? There are dozens of websites out there that let people download skins and themes. But there's only a handful that are really dedicated to it and have the bandwidth to support lots of users.
WinCustomize is the Walmart of Windows customization. It specializes only on the most popular skinnable programs and is designed to make it easy for users and skinners to get and submit skins, themes, icons, walls, etc. It is also owned by Stardock which makes popular skinnable programs such as WindowBlinds, ObjectBar, DesktopX, IconPackager, etc. This has helped make it the most popular "skin site" in the world. WinCustomize has tended to highlight its sections as the applications that have made it to the "big leagues". For users looking for skins for little known programs, WinCustomize wouldn't be the place to go. But if you're looking for icons or PNGs or Windows Media Player skins or wallpapers or WB visual styles or SysMetrix skins and so forth, WinCustomize would be the place to go.
deviantART isn't a skin site. It's an art community that happens to have skins. And over the past year, it has come to be the world's most popular art site. Its popularity has been earned the old fashioned way - it was simply vastly better than other similar sites that existed and over time it won over users from around the world. If WinCustomize is Walmart, deviantART is the art wholesaler. While not a "skin site" per se, it does contain a wealth of skins, themes, and icons as part of its overall mission of supporting art in all forms.
ArtUproar used to be called LotsOfSkins. At some point, most customization sites reach a fork in the road. Is their constituency the artists who create the content or the users who use the content? At some point, LotsOfSkins made that choice -- a place for artists to hang out and became ArtUpRoar. It has remained quite popular though obviously over shadowed by deviantART. On the other hand, it provides a bit more intimate atmosphere for artists and users alike to hang out and interact. Highly recommended.
SkinBase could be called Encyclopedia Themica. That's because it offers the most comprehensive support for skinnable programs of any site. It contains statistics of all kind that are useful to both skin/theme authors and users alike. It recently went through a heavy redesign which integrated some good ideas from other sites (such as a much cleaner interface) combined with its own innovative twists that make surfing the site very easy and efficient. Another nice thing about Skinbase is that like LotsOfSkins, it's a very friendly place. Anyone who surfs the net long enough knows how nasty parts of the Internet can be. Going to a site like Skinbase can feel like getting into shelter from a downpour. You have to visit it to see what I mean, it's just a very friendly place to be at.
Skinz.org has a long and inconsistent history. It has changed hands many times and the newest owners are working to try to bring it back to a semblance of its former glory. It has an up hill climb, however. Sites like deviantAR and WinCustomize have effectively carved up the niches that Skinz.org used to specialize in.
Customize.org was really the first dedicated skin site. It has changed owners over the years but the mission has remained the same. What makes Customize.org unique versus other sites is that its library is the oldest. That means you can actually go back and find the very first skins ever created. For me, that's a big deal because it's fun to see how far things have come. It doesn't hurt that it serves as a reminder to the "commercial software is evil" zealots that programs like WindowBlinds were here at the start. So what was the first WindowBlinds skin on there? Oh the shock, a skin that combined BeOS and MacOS from December 1998 (5 years ago!).
The others...
There are other sites on the net that have skins and themes but we focused on sites that have at least a half dozen different sections (otherwise we'd be stuck having to cover every wallpaper site or every theme site which would be painful). But there are other interesting sites on the net that are worth checking out. There's Neowin.net which is a tech site but has arguably the best message forums on the net. There's ThemeXP which has lots of logons, boot screens, msstyles, and wallpapers. There's also Hardware Geeks which is like a sister site to Neowin. Where Neowin specializes in talking about software technology and more, Hardware Geeks focuses a bit more on the hardware aspects. There's also eMaculation.com whose admin regularly rips on me but that doesn't change the fact that the site has lots of useful informaton. There is also Aqua-Soft which is full of tips and content that help you transform Windows into looking like MacOS X.
Conclusions
Hopefully this little primer will help you get started. This is by no means the definitive answer to skinning, theming or customization in general. Heck, as a Stardockian, it would be best if someone else wrote this, but no one has and I get so many email from people asking for help and information on what is what that it was time for someone to write something on this to get people started.
Email me: Bradley Wardell