I've played all the Super Smash Bros. series games - my favourite is Brawl.
I don't mind admitting that I've been a Sonic fan for longer than I can remember, but I hate to say that I haven't played as him anywhere near enough on Brawl.
SSB Main: Pikachu (there's a reason why he's top of the tier)
SSB Second: Donkey Kong (power characters rock)
SSBM Main: Mewtwo (just amazing to play as, I was really disappointed when he wasn't kept on for Brawl)
SSMB Second: Roy (good combos, good damages)
SSBB Mains: Meta Knight (clearly the best), Snake (clearly the second best), King Dedede (lots of finishing moves)
SSBB Seconds: Marth (good overall gameplay), Ike (strong finishing moves)
I can't stand Jigglypuff and Olimar, but only because whenever I play as them, I lose, and whenever I play against them, I lose. I've never got the hang of Wolf - I find him slow, clunky and ludicrously heavy, but without the extremely powerful finishing moves that you would expect from character of his size.