Hmm... Let me see what's MY favorites.
MM1: I like Ice Man. He just looks pretty cool.
MM2: This one was kinda tough, but... I like Bubble Man. His stage is awesome, along with his theme.
MM3: Magnet Man. HANDS DOWN, Magnet Man.
MM4: It's a tie between Dust Man and Bright Man. I love both of their themes, and their stages are nice too. Although, I like all of them from this game.
MM5: I love Wave Man, and Charge Man is nice too. Mainly because of there awesome themes and stages. Gravity Man and Crystal Man tie for best design in my opinion, but I like all of them from this game.
except stone man... (shudders)MM6: Either Knight Man or Yamato Man, because they are the only ones besides Blizzard Man that aren't stupid and sterotypical.
MM7: I like Burst Man from this game. He looks pretty cool.
MM8: Aqua Man. I like his stage, and plus he's handsome.
MM9: Ooh... Either Concrete Man or Hornet Man. Concrete Man is a tank, while Hornet Man is cool.
MM10: My favorite here is Strike Man, because he's freakin amazing!