I've always liked Luigi, and Bowser can be OK I guess, but the rest could all die for all I care. Actually, that's not true... I would care greatly, in a joyous kind of way.
I hate Mario and Mario games. I always have since Super Mario Bros. 3. That one was alright.
Edit: Man, what'm I thinking?! Dry Bones and Red Koopa Troopas. I'd play a game with just them.