Fawlty Towers, often v funny (esp. The Germans, and the one where the guest dies)
Blackadder, yes, but have got tired of it from over-exposure
Python, of course ("no, it's spelt Raymond Luxury-Yacht, but it's pronounced Throatwobbler Mangrove")
Marx Bros (esp. Monkey Business - v surreal - Night at the Opera, Duck Soup - esp. the mirror sequence): comedy as an art form
Friends, though the number of amusing one-liners has declined, and I really do want to smack all of them
Mr Bean has gone right downhill lately, relying on tired comedy clichés. The Christmas edition was fun, however.
People/things where I can't understand the comic appeal:
Mel Brooks (except Young Frankenstein)
Fart jokes
Farrelly Bros films
Benny Hill
Much of Laurel & Hardy (except Way Out West, which is a nice, unassuming amusing picture)
Anything in which animals are injured (or apparently injured) - exceptions include my favourite joke:
Q. How do you make a dog drink?
A. Put it in a blender.
(Are we going to start a 'Favourite Joke' thread?)
There was a time when I couldn't see the appeal of Seinfeld, but the BBC have been re-running the episodes lately, and I must admit I was entertained.