Hm, as long as they don't get rid of any old characters I'm okay with whoever they add in. There's always the obvious Sonic or whatever (although his companions Knuckles and Shadow are more fighters than he is) but, I won't start that argument up again.
DIDDY KONG
B-Up = Jetpack
B-Side = Chimpy Charge
B-Down = *thinks of DK64* I can't remember my idea =/
B-Standard = Peanut Pistols
FSA = unknown...Primal Rage? Suggested by someone who's played Strikers =P
LANKY KONG
B-Up = I can't remember the name, but he stuck his thumb in his mouth and blew and he got fat and started floating...
B-Side = Kinda like Jigglie's B-Side move, but with his longer arms it should be more effective...
B-Down = Stand on his head and spin around (like an upside-down version of DK's B-Up) I think he did it in the DK64 intro movie...
B-Standard = um...the Grape Shooter?
FSA = iono...Trombone Smash? He's wacky so he could do pretty much anything as his FSA =P
BOMBERMAN/MAX
Both from the Bomberman series, prolly just clones...I can't think of their moves right now though...
MEGAMAN
I've actually never played Mega Man, but he looks pretty cool...
KANDEN/TRACE/SPIRE
My personal favorites from Metroid Prime: Hunters =P Also good are Sylux and Noxus, but I just put the ones I use most although the latter both look cooler than Spire...
SLIPPY/KRYSTAL
Well, both from Starfox, I now understand why Falco is a clone of Fox...but I think he and Slippy have been prominent enough in the past games to have their own movesets, and Krystal would use her staph...
That's all for now...but I've cycled through many ideas thinking about sending in mine for SSB

S...but it's pretty much been halted until we see what other characters will be in Brawl: I'm tired of changing my already crappy drawings =P