You have to go by role for this.
Starting pitcher - Halladay, and he is without a peer in the majors. The guy is so much better than his numbers, its ridiculous. You don't see it until you watch him.
Hitter - Pujols. As I said before, Utley is a distant 2nd. Arguing between Howard and Votto is ridiculous. Those guys shouldn't be in the conversation - they don't bring what Pujols and Utley do. When the pressure is on, does anyone ever really say, "I sure wish Joey Votto was coming to the plate." Hell no, you want Pujols or Utley, and probably no one else.
Closer - Do I even need to say his name? The Yankees signed the saves leader in the AL to set him up.
Defense - Mauer if I can cheat and count his offensive production. If it's pure defense, it's going to be a shortstop. I really don't know who I'd take here.