I cant believe that Chelmsford 123 hasnt been mentioned! Jimmy Mulville and Rory McGrath were brilliant in it, McGrath particularly.
Nightingales is fantastic too, well worth hunting that down.
I bought the Peep show box set series 1-6 from HMV recently which was really good, i kept missing it when it was on so it was nice to watch it all in a week!
Game On was also quite good but then maybe that was just because it had Samantha Janus in it and I was 14….
My favourite ever tv comedy though was Bottom… 30 minutes of complete anarchy!