Haffey and Aragon are the best today. David Sizemore will be in the near future. And there are three young skaters outside the U.S. who will be great - Julien Cudot in France, Rian Arnold in Australia and Fabio Enes in Brazil.
From the older guys I've seen in videos, I really liked Dustin Latimer for a smooth style, and Aaron Feinberg for doing crazy tricks.