I'm no expert on British comedy either (I say it in case i 'm exposed to severe castigation if any gaps in my knowledge concerning this partucular art come to light;)
HOwever, I'm a great fan of Keeping Up Appearances, MontyPython (feature films as well as Flying Circus and aforementioned Fawlty Tower). I also enjoy Black Adder.
As for American comedies, mpst of them don't apeeal to me, however there are sure to be found a couple of series and feature movies whoch give me a real laugh, like the BUndies, initial episodes of Third Rock From the Sun or Shrek.
The last time i was laughing like hell, was while watching Madagascar (POlish dubbed version), and I strongly recommend this one;)
As for POlish comedies, I must admit, I got a little tired of old Poilsh comedies, as I've seen them too often, but Dzien Swira was hilarious, or Kiler. I'm probably not too demanding, as you may see, as i enjoy laughing, so I'm not that picky, but JIm Carrey? no thank you.
Rgds,
KOciamama.