Yup, just after 2 days of the games first release in Hong Kong we have the entire Roster of Veterans and Newcomers; a total of 35 playable characters! i'm going to make this short, sweet, and to the point, so without further adieu, I present, the complete Super Smash Bros. Brawl Character Roster:

NOTE:
Samus and ZeroSuit Samus are counted together, although they are not listed together (otherwise one would think it was 36).

VETERAN FIGHTERS:
Mario [Mario Series]
Luigi [Mario Series]
Yoshi [Mario Series]
Peach [Mario Series]
Bowser [Mario Series]
Donkey Kong [Donkey Kong Series]
Kirby [Kirby Series]
Pikachu [Pokemon Series]
Jigglypuff [Pokemon Series]
Fox [StarFox Series]
Falco [StarFox Series]
Zelda/Sheik [Legend of Zelda Series]
Link [Legend of Zelda Series]
Ness [Earthbound Series]
Ice Climbers [Ice Climber Series]
Samus [Metroid Series]
Captain Falcon [F-Zero Series]
Marth [Fire Emblem Series]
Gannondorf [Legend of Zelda Series]
Mr. Game&Watch [Game&Watch Series]

NEWCOMERS:
Solid Snake [Metal Gear Solid]
Pit [Kid Icarus]
Meta Knight [Kirby Series]
Wario [Mario/Wario Series]
ZeroSuit Samus [Metroid Series]
Ike [Fire Emblem Series]
Diddy Kong [Donkey Kong Series]
Pokemon Trainer [Pokemon Series]
Lucas [MOTHER 3- Earthbound]
Sonic the Hedgehog [Sonic Series]
King Dedede [Kirby Series]
Pikmin & Olimar [Pikmin Series]
Lucario [Pokemon Series]
Toon Link [Legend of Zelda Series
R.O.B. [Gyromite & Stack-up]
Wolf [StarFox Series]

[Source: Everybody who played SSBB and unlocked all the Characters; Official Brawl Website]