Eggman
Smash Apprentice
Dude, NiGHTS would be kewl. He could fly around the stage and hit random people, like Scissor (sp?) from Melee, except longer, faster, and more chaotic. Protoman would be a killer one too, along with Roll (she'd be the "Chansey" of AT). As far as Sonic goes, odds are it will be Tails. Tails is Sonic's Luigi (anyone who doubts this should go play all the Genesis Sonic games starting with 2) and, I think, will be the Sonic AT (assuming he's not a PC)...if they only allow one.