Fawlty Towers. The first series was submlime, the second series merely breathtaking.
Sitcoms that peaked in series 1 Page 6
I'm Alan Partridge
Spaced
Extras
The Office
Marion and Geoff(solely because it suits a shorter length)
Frasier(sorta, Seasons 1-4 are all equal)
Undeclared(obviously)
The IT Crowd
Outnumbered(the boy seems very flat in series 2)
Just read through the thread, Series 1 of Partridge is infinitely better than 2. Not even sure why entirely, I think Coogan may've declined a bit as the character. Not saying 2 is bad, just 1 is perfect.
Most of Black Books series 2 seemed to be as good as series 1 in my opinion, 3 was considerably weaker though.
Quote: sardines @ July 8 2009, 5:24 PM BSTJust read through the thread, Series 1 of Partridge is infinitely better than 2.
Not to me. I'm going to continue standing up for series 2, because it's great! 
Quote: Matthew Stott @ July 8 2009, 5:25 PM BSTNot to me. I'm going to continue standing up for series 2, because it's great!
Have you rewatched it much? I loved it first time round.
Men Behaving Badly and Black Adder
Quote: sardines @ July 8 2009, 5:24 PM BSTUndeclared(obviously)
?
Quote: Aaron @ July 8 2009, 6:16 PM BST?
Only 1 series, innit?
Quote: Aaron @ July 8 2009, 6:16 PM BST?
Fantastic American sitcom by Judd Apatow.
IMO, I would have to say Game On
Quote: sardines @ July 8 2009, 5:27 PM BSTHave you rewatched it much?
Yes, why?
Quote: sardines @ July 8 2009, 8:02 PM BSTOnly 1 series, innit?
Dunno, never heard of it. 
Quote: Tom G @ July 8 2009, 5:32 PM BSTMen Behaving Badly and Black Adder
The topic is sitcoms that peaked in their first series is it not ?
Yeah. They were both shite.
Not Going Out
I'm Alan Partridge
Garth Marenghi's Darkplace
and non-British
Flight of the Conchords.
I still like them all, though.
Not Going Out I thought was consistantly good-ish.