Don't forget my favorite, A-Basin, for excellent high-mountain intermediate and advanced terrain! The eastern wall (extreme skiing only) is at 13,050 feet, higher than any other ski terrain in North America. The blue and black runs top out around 12,400 feet and have amazing views across the mountain range. A-Basin is in Summit County, ten minutes east of Keystone on Highway 6.
http://www.arapahoebasin.com