Kirby and MetaKnight are two of my favorites, more the former than the latter. Kirby's Final Smash has to be among the best in the game. It can be both offensive and defensive, depending upon the items thrown out after the launch. Link seems much worse to me than he was in Melee, but that's probably just me. I never used (adult) Link much.
Ice Climbers can be pretty formidable, until they're split up. Then you might as well just drop offscreen.