Yep Peep Show is a real classic too, every season in fact. Then of course there are the first 6 seasons of Red Dwarf.
My favourite comedy of all-time is the old series The Fall and Rise of Reginald Perrin. It was quite unusual in it's day.
Disillusioned after a long career at Sunshine Desserts, Perrin goes through a mid-life crisis and fakes his own death. Returning in disguise after various attempts at finding a 'new life', he gets his old job back and finds nothing has changed. He is eventually found out, and in the second series has success with a chain of shops selling useless junk. That becomes so successful that he feels he has created a monster and decides to destroy it. In the third and final series he has a dream of forming a commune which his long suffering colleagues help bring to reality. Unfortunately that also fails and he finds himself back in a job not unlike the one he originally had at Sunshine Desserts.
Nighty Night is fucking great and dark.
The Royale Family is so funny coz so much of the humour is true to life.
