My top few:
1. Jackson Hole, WY: look here for the most diverse terrain, length of runs and excellent personal instruction that doesn't necessitate a mortgage. Jackson has become alot more expensive over the last 6 years, but the whole experience of the Tetons, the Tram, the Moose bar at the base, the Cowboy bar in town and Wyoming hospitality make this a world class hill.
2. Alta, UT has some of the best chutes, wild terrain and the Iron Horse Grill: best ski resort food you will find.
3. As Strut said, Brianhead has some of the best powder at a decent price, and lodging is much cheaper than at most serious ski areas around.
4. I'm anti-snow board (cause they wreck my damn moguls), but Brighton is probably one of the most board-friendly in the country. It's also an incredible place for early morning POWDER from hell!
5. Winter Park/Mary Jane, CO is one of my all-time favorites. You get the huge terrain, runs for any level of experience, and faster/shorter lines than most anywhere in Colorado.
If you want a seriously diverse ski trip though, try a week in Salt Lake City. You can be at any of 15 ski resorts within 45 minutes or so. Most hotels in SLC have shuttles that will get you in and out quick.
http://www.utah.com/ski/resorts/