Few will enjoy them all, but my serious recommendations are:
Buffy the Vampire slayer. Put your snobbery in a box, and at least try the first season, before you turn your nose up at it. Advise from some one that regrets missing this on TV. Takes a few episodes before the mythology starts to kick in, but when it does...
24. The first season was very, very good.
Fire Fly. It's only 14 episodes, but what a 14. Cowboys in space work well, here for some reason.
Ranma 1/2. I'm sure there are haters out there, but anime fan or not, I have yet to show this to some one that didn't like it. There is nothing, even in Japan, that comes close to this brand of strangeness, and no explanation that does justice. Just check the first episode, most of the time, it's enough to reach for the second.
Corner Gas. Yes, it's a Canadian plug, but it's also the only sitcom I've enjoyed, and is funny, in like 10 years.
Band of Brothers. A little less exciting than Saving private Ryan, but more realistic.
History Bites: Give it try, it's comedy, and if you like it, the things you could learn.
M.A.S.H. What is wrong with you? Do you own a television?
Ghost in the shell: Stand Alone Complex. Easily one of the most rewarding series out there. Fans of the movie will find this far easier to follow, but if the first episode confuses you, this may not be the series for you.
ROME. If you are familiar with the story of Julius Caesar, watch until at least the second episode. If you are not, well, there is a major hole in your understanding of history, and this is about the most entertaining way to fill it.
Neon Genesis: Evangelion. It's a coin toss if you will understand the ending, but is the single greatest pay off I have ever gotten from television. If you don't enjoy it by episode 4, you should probably stop.
I've noticed some people who seriously want to contribute into making a Spill movie, or at least a Spill fan film. This group is to discuss things like writing, production, etc... You guys have a crack at it, I'll just moderate. Have Fun!