Okay, let me think about it...
East (includes Canada):
1. Stowe (tie) VT - Great terrain, challenge, variety and fall line skiing. The scenary isn't bad either.
1. Sugarloaf (tie) ME - same as Stowe + snowfields
3. Whiteface NY - Best vertical, Fall line, groomers. The price is right.
4. Mad River Glen VT - A trip in Mister Peabody's WayBack machine. Why skiing was great back then... Great terrain and challenging. No manicured runs here. You against the mountain and the elements.
5 . Ste-Anne QC - Best skiing and best mountain in Quebec. Fall line, steeps, no flats + great and reliable snow.
5. Smuggs VT - A more modern MRG. Great terrain and twisting trails.
7. Sugarbush VT
7. Jay VT
9. Sunday River ME - McSkiing and not as crazy as Kmart. Fun groomers.
10. Killington VT - Is a beast, but it's not all bad.
Not in the Top10 but not far (more or less in order):
Wildcat, Cannon, Tremblant, Burke, Massif, Orford...
Eastern Canada (note - only Ste-Anne makes the Eastern Top 10).
1. Ste-Anne QC - Way above the rest.
2. Tremblant QC - Fun, but a zoo... Also more geared for the intermediate skier.
3. Le Massif QC - Best views in the East and greatest vertical in Quebec (close to 800meters).
4. Orford QC - Great steeps, crazy glades.
5. Sutton QC - Glades and atmosphere.
I haven't skied Massif du Sud and Mont Edouard which I've heard great things about.
West (includes Canada):
1. Whistler/Blackcomb - Everything, maybe too much.
2. Alta/Snowbird UT - I need maybe to ski more to make a better judgement, however it's doesn't have the Whistler zoo effect which is a BIG positive.
2-3 or 4. Jackson Hole WY - Crazy and challenging. I've had 3 out of 4 amazing condition days, however this could potentially be a #3 or 4.
4. Mammoth CA - I've skied in June and July. But I've seen the map and the mountain. Definitely Top 4.
5. Lake Louise AB - Groomers on the Front side and Bowls in the Back.
* See note
I won't mentioned the rest as my experience in the West is limited: other places that I have visited not mentioned (not in order):
AB: Sunshine, Norquay, Marmot, Fortress
MT: Bridger, Big Sky/Moonlight
WY: Targhee, Snow King
1. Val d'Isère/Tignes FR
2. Les 3 vallées FR (Courchevel, Meribel, Les Menuires, Val Thorens)
3. Les Arcs FR
Other areas I've seen, but not in same category as the Top 3.
FR - Flaine, Brevent/Flégère, Grand Montets, Vallée Blanche, Alpe d'Huez, Chamrousse.
IT - Courmayeur
SW - Jungfrau (Grindelwald, Wengen, Murren)