Keystone is my favorite. Maybe it's the fact that the mountains are behind each other and when you get off the crowd-crazy front slopes you are in a beautiful, quiet place. Maybe it is the ice skating in the middle of the complexes. Maybe it's the family-friendly ski school. Breckenridge has a great town with lots of food and atmosphere. Vail is just a high-scale creature of its own. Copper mountain is more laid back and rough around the edges.