I'd go with Bugs, personally. Mickey's too much of a wussy goodie-goody, while Bugs is a bit more of a charismatic, cheeky arsehole. Shite catch-phrase, mind you.
Mickey and Sonic are kind of alike... except Mickey wears pants.
I'm thinking Bugs too. He's a helluva lot more funnier, plus it doesn't seem right seeing Mickey running around in a black cloak wielding a Keyblade, lol...You know Mickey has a dark side though... after all those years of living with Minnie and trying to understand Donald... he HAS to have a dark side.
wHAT ABOUT DUFFY DUCK??????
Taz FTW.