There aren't too many shows that I dislike, but not too many that I have to watch every episode.  I've always enjoyed Curb Your Enthusiasm, Family Guy, The Shield, It's Always Sunny In Philadelphia and most times Survivor.  Also, I miss the reality show 'The Mole'.
The one show that I really just don't get, and I'd have to say is considered one of the most popular, is Two And A Half Men.  I have yet to snicker or chuckle once during that show.  Maybe I just find it too predictable.  A close 2nd would be Big Bang Theory.