Edit: 1 last char, and final tally:
yup here it is, the final list of playable chars in SSBB (as leaked from a japanese souce, where the game is supposed to be released on Jan 31, but was opened prior)
There are many Smash Bros. newcomers, like:
1. Diddy Kong (from Donkey Kong Country),
2. Ike (from Fire Emblem),
3. King Dedede (from Kirby),
4. Lucario (from Pokemon),
5. Lucas (from Mother 3/EarthBound 2),
6. Meta Knight (from Kirby),
7. Pikmin & Olimar,
8. Pit (from Kid Icarus),
9. Pokemon Trainer (controls 3 Pokemon, you switch between Squirtle, Ivysaur, and Charizard to fight),
10. R.O.B. (Robotic Operating Buddy — from Gyromite & Stack-Up),
11. Solid Snake (from Metal Gear Solid),
12. Sonic the Hedgehog,
13. Wario,
14. Wolf (from Star Fox).
Lots of veteran characters from the original N64 Smash Bros. or its Melee GameCube sequel will return, they are:
15. Bowser (from Mario),
16. Captain Falcon (from F-Zero),
17. Donkey Kong,
18. Falco Lombardi (from Star Fox),
19. Fox McCloud (from Star Fox),
20. Ganondorf (from The Legend of Zelda),
21. Ice Climbers,
22. Jigglypuff (from Pokemon),
23. Kirby,
24. Link (from The Legend of Zelda),
25. Luigi (from Mario),
26. Mario,
27. Marth (from Fire Emblem),
28. Mr. Game & Watch (from classic Game & Watch games),
29. Ness (from EarthBound),
30. Pikachu (from Pokemon),
31. Princess Peach (from Mario),
32. Princess Zelda (and her Sheik transformation after using the down special move),
33. Samus Aran (and her Zero Suit Samus transformation after using Final Smash — from Metroid),
34. Yoshi (from Mario),
35. Young Link (from The Legend of Zelda: Wind Waker).
Characters who did not return from Smash Bros. Melee are:
* Dr. Mario,
* Mewtwo,
* Pichu,
* Roy.