Ooh, Prison Break is good. I nearly ripped my fingernails off during the first season, so much tension!
In no specific order:
Biggest Loser
Big Bang Theory
Buffy/Angel (Classics, I tells ya!)
Extreme Makeover: Home Edition
The Young and the Restless (I've been watching since Day 1, and I love it still)
And, because it's on at my gym when I work out, Earth: Final Conflict. Over the noise of the elliptical, I can't hear anything, so I don't know what anyone's voice sounds like, but I read the closed captioning.
And Law and Order: Special Victims Unit gets me every. single. time.