I threw out my tv years ago and I still haven't replaced it, although I'm tempted. About a month ago, I borrowed a bunch of shows from my friends, and then I got hooked on two of them.
The shows I'm really hooked on
1) Grey's Anatomy
2) House
(I see we have a lot of House fans here :)
I haven't been this hooked on a tv show since The X files (not the last 2 seasons, before Mulder left the show).
These are not in any particular order
3) Stark Trek: TNG
4) Sopranos
5) The X-Files
I'd probably be willing to throw Monk up there on the list as well, but I haven't been able to watch any more of it other than part of the first season.