I've had a trawl, and couldn't see that this had been done, so I thought I'd give it a go.
In order
5)Papa Lazarou - League of Gentlemen
4)Anthony Hancock - Hancock/Hancock's Half Hour
3)Edmund Blackadder - Blackadder
2)Ari Gould - Entourage
1)Basil Fawlty - Fawlty Towers
Mentions for Jack Donaghie (30 rock), Martin Ellingham (Doc Martin), Jim Royle (Royle Family), Marty Craine (Frasier), Kramer (Seinfeld), Gareth & David (The Office)...
There are baiscally too many to have a top five, so the first five that spring to mind right this second are:
Blackadder
Partridge
G.O.B
Liz Lemon
George Costanza.
Or how about:
Rimmer
Dwight Schrute
Tobias Funke
Bernard Black
Mark Corrigan
There's too many!
Partridge should've been on me list
Del Boy Trotter
Rodney Trotter
Trigger
Dougal (Father Ted)
Victor Meldrew
Basil Fawlty
1) Stewie Griffin (although not sure about the episodes after Season 5-even some episodes in Season 5 were not as good)
2) Peter Griffin (the same applies to Peter as it does to Stewie above)
3) Edmund Blackadder.
4) Bender (though I'm not that keen on anything after Season 4-when it started to go downhill)
Not sure about the fifth character-might come back to this one.
1. Gary Sparrow (Goodnight Sweetheart)
2. Assumpta Fitzgerald (Ballykissangel)
3. Miranda (Miranda)
4. Christine (2point4 Children)
5. Basil Fawlty (Fawlty Towers)
Quote: David Carmon @ May 1 2010, 12:44 AM BST1. Gary Sparrow (Goodnight Sweetheart)
That's got to be quite unusual!
Why is he your favourite?
It is my favourite sitcom/ TV show ever in the entire world. Plus I want to time travel and I lived my dream through him haha
I just like the fact that he cheats on his wife, then gets married in the past and continues to cheat on both wives, have a baby, use his best friend and still be likeable at the end of it all.
Haha! Fair enough.
You love it even more than 2point4 Children though? 
Yes. But ssshhhh 
Goodnight Sweetheart was with me first (I didn't get into 2.4 till 1994)
2point4 Children is my 2nd favourite sitcom but only around my 4th or 5th TV show I think.
Im very very very sad and geeky.
Join the club. 
Dwight Schrute
Senor Chang (Community)
Charlie Kelly (Always Sunny)
Vulva
Derek Grimm (i.e. me)
I'm sure they're huge in The States.
Mine
Fawlty
Manuel
Sybil
Major
Polly
Quote: Alfred J Kipper @ May 3 2010, 12:09 PM BST
I'm sure they're huge in The States.
Maybe you should give some American comedy a watch then? Hmm? There are just as many great comic creations over there as here.
Quote: Alfred J Kipper @ May 3 2010, 12:09 PM BSTMine
Fawlty
Manuel
Sybil
Major
Polly
Kind of limited in scope there, yes?
Mine:
5: Soldier Gloria Beaumont (from it ain't half hot mum)
4: Emmet (from Keeping up Appearences)
3: the stupid Prince-Regent from Blackadder the third
2: Andy Pipkin (Little Britain)
1: Basil Fawlty of course :-)