Ok, sticking with well-known, highly visited places
Alta (The above three earned their reputations and remain, rightfully, the premier destinations for serious skiers).
Killington (it's everything people say, the good and the bad…the Former outweighs the latter on most days)
Sugarloaf (Best overall in the east, by reputation and fact).
Greater Tahoe: Of all the ski regions I've visited, this is the one it pays the biggest dividends to resort Hop. Squaw is the crown jewel in the region, of course.