It depends on which kind of AMC you want.
Playing with Atlético Madrid, I'd say they have the three best on the game, and they are all different types of players.
Sergio Aguero; very attacking AMC, who'll score a lot of goals running through the defence.
Raul Garcia; Isn't the fast dribler Aguero is, but he's one hell of a player if you play him more defensively and let him control the game. Probably won't score many or either make lots of assists, but he'll control the game like no-one else.
Emiliano Vecchio; Still very young at the start of the game, so will need a couple of seasons to start playing well. Also a very offensive player, but will control the player better than Aguero and probably make more assists.
Here he is aged 20. Not many players have better offensive stats!