Very tough call. Bronze medal has to go to Dr Alan Statham from Green Wing...
Coming in an honourable 2nd place, I'd say the three main characters in 'Yes, Minister' - yes, slightly cheating in that they're technically an ensemble but you couldn't have one without the others!
However, there's no doubt that number 1 on my list is General Sir Cecil Anthony Hogmanay Melchett, of Blackadder series IV fame - boisterous, ridiculous, manic and armed with the best moustache in television history. BAAAAH!
Tough question, as there are so many great comedy characters to choose from, even though other people have already picked three superb ones: Jim Hacker and Sir Humphrey from "Yes, Minister", and Bernard Black from "Black Books".
When I was thinking about the answer, though, and going through all my favourite sitcoms in my head, I realised that - in a lot of them - there's no one particular character able to be funny on their own, without playing off one or more of the other characters in the show.
Many great sitcoms seem to be a team effort, and it's the strength of the ensemble cast (and the writing) that makes them so funny - such as in the great shows I've listed below:
Peep Show
Friends
Gavin and Stacey
Getting On
That realisation narrowed the field a bit, as far as my favourite sitcoms go - and so my shortlist ended up comprising the three mentioned above, and in James and Harry's answers, as well as the characters below:
Homer Simpson (if we're counting The Simpsons as a sitcom)
David Addison in Moonlighting (again, if that counts as a sitcom)
David Brent, in The Office
Basil Fawlty, in Fawlty Towers
My final pick, though, is from Married With Children - the horrendously politically-incorrect Al Bundy, disaffected husband, father and shoe salesman, played by Ed O'Neill.
The show ran for 11 seasons, between 1987 and 1997, and every scene featuring Al still has the power to make me cry with laughter.
This is a difficult one - quite often, it's not just one character that stands out, but the relationship between the characters.
For me, Dougal, Ted and Jack from Father Ted work brilliantly together — it's the group dynamic that makes the show so funny.
Tim from Spaced - it's great seeing Simon Pegg and Nick Frost working together before they got big, and I think this is much better than their later stuff, as it seems effortlessly funny. Sean of the Dead and Hot Fuzz were great, but Spaced just seems so much more natural and relatable (and a lot more geeky!).
Bernard Black from Black Books. Again, I don't think it would be half as funny without Manny and Fran, but Bernard always stands out as being the most funny (and relatable!) character.