A-rod, Reyes, Sizemore, Felix, Cabrera, Pujols and Wright are my top candidates. Papelbon, Lincecum, Hamels, and Mauer are good choices too but on the bubble for me. Mauer for durability concerns, 2/3 major league seasons have been derailed so far and Hamels and Lincecum are relatively untested and Papelbon is a reliever so I can't mention him up there with Felix and the guys who play everyday.
Out of all of those if I had to pick one to start a franchise with tomorrow, I would go King Felix. Pitching is what good teams are built around, and every good staff has to fall in line behind the ace and this guy is 21 and has some of the best stuff I've ever seen. If this were one of those video game fantasy drafts, he'd be my number one pick. He has a chance to be amazing.