This is hard one because I love TV! The invention of the DVR + my schedule as a nurse = lots of free time to watch TV. I am a big fan of HBO and Showtime series, not much a reality TV watcher.
If I have to choose, my favorite show that is not on the air anymore is Sex and the City. I still don't know who I love more, Aidan or Mr. Big.
Of the TV shows I currently watch - there are a lot - House, Bones, Criminal Minds, Grey's Anatomy, The Office, Entourage, United States of Tara, Hung, Weeds, Dexter...
Favorite Comedy - Glee. It always cracks me up.
Favorite Drama - True Blood. I would let Eric Northman bite me anytime :-)