Brains - Iron ManAnd Hawkeye doesn't get one of these because he's so uncomfortably the bastard stepchild of the group . The mere fact that I just wrote one sentence about him means I put more thought into his character than the people who made the movie.
Looks - Captain America, as the face of the team
Muscle - Thor
Wild card - Hulk
Useless girl - Scarlett Johansson