Firefly for sure.

Babylon 5 (have to watch the first 5-6 episodes before it starts to get better. A lot is building for the 5 season series and it really is worth it.

Fringe is a good show as described above.

Jericho (another show that was canceled after a year or so that was good).

Cowboy Bebop is excellent (1 season)

Farscape is very excellent (4 seasons)

All sorts of neat stuff out there!!!

I would rate Doctor Who highly.  If you wanted you could start with Series 1 of the new series if you can still get it.  I think all the new series are pretty good, the production values are high and there aren't too many obviously bad episodes and a lot of really great ones.

When it comes to sci-fi/fantasy and a real humanistic, life-affirming outlook (even though there are lots of aliens and a few deaths ) there's not a lot better than the new Doctor Who series 1-6 (and after).  And you said you had a bit of time...

PS: Oh no, my avatar is an alien!  I assure you that I am quite human.

Cajun cookin' with Justin Wilson! Ooohwee!

ohh...and Grimm looks cool. I think i have to watch this.

Fallen Skies

BEST

Dexter (! plain awesome on every level)

House (for the cleverness)

Breaking Bad (goes truly insane after a while)

Chuck  (makes me laugh or smile a lot)

GOOD

Firefly (just good as you have 1 season only...)

Lost (incredible, but that ending...)

Fringe (both truly great AND truly bad episodes)

If you want to laugh 

The Big Bang theory

Here's 3 that should be on your must watch list....

Boardwalk Empire

Deadwood

Game of Thrones

Also, the best way to watch one of these series is "HBO GO". They have every episode available, on demand.

That's two Big Bang Theories.

+2 for Fringe and MI-5 (Spooks to Jafo, though yes, people tend to die)

Kris

-1 for people who suggested TBBT, that show has stop being about geeks using science in their everyday lifes, but rather back to where every comedy is right now.

If you are a follower of modern culture, you might want to watch Community.

However, Fringe is a great series to watch. I watch the pilot episode of The Wire and got really bored.

Oh, and "Missing" .... current thriller series

"Once Upon a Time"... a fairy tale with a modern twist

+ 1 for "Game of Thrones".... also, "Legend of the Seeker" but less blood

.... and "Roar"  a Medieval-type fantasy... has Heath Ledger before the Batman crap

Community is easily the best comedy, but you got to watch it from the start to get the feel.

Fringe is a great sci fi, recommend it to every sci fi junkie.

I think Draginol already 've seen it.

Vorlons - Arnor

Shadows - Dread Lords

I've heard excellent things of Downtown Abby.

We just finished watching "Doc Martin". Excellent blend of drama, comedy, mystery, romance, and character study.