Bowser: 70:30
Captain Falcon: 100:0 (LOL match-up)
Diddy Kong: 38:62
Donkey Kong: 60:40
Falco: ?
Fox: ?
Game & Watch: 35:65
Ganondorf: 68:32
Ice Climbers: ?
Ike: ?
Jigglypuff: ?
King Dedede: 63:47
Kirby: ?
Link: ?
Lucario: ?
Lucas: ?
Luigi: ?
Mario: 50:50
Marth: 35:65
Meta Knight: 42:58
Ness: ?
Olimar: 30:70
Peach: ?
Pit: ?
Pokemon Trainer: ?
R.O.B.: 40:60
Samus: ?
Sheik: 60:40
Snake: 50:50
Sonic: 60:40
Toon Link: 48:52
Wario: ?
Wolf: ?
Yoshi: ?
Zelda: ?
Zero Suit Samus: ?
These are just my opinions on the match-up ratios (except the MK one, which i got from somewhere else); feel free to discuss them here.
Also sorry for so many blanks, they're either because i've had very little experience in that match-up or because i haven't played any good players with those characters.