I don't watch as much as I used to, 10 years ago (I was a student and had more time, to be fair). These days my favourites are:

Doctor Who - really got into this the past few years, love it!

The Simpsons - I still love it, a lot of people don't like it any more but I do.

Family Guy - just as ridiculous as ever!

The Big Bang Theory - got into this from the first series and think it's really brilliant.

I still watch my Frasier DVDs a lot, and Friends is still running on telly every day on E4 so I often watch that too - they just never get old!