in the US go mammoth, for canada go whistler.
as for california,  i prefer squaw for challenging terrain, but for your first time out west mammoth is your best bet,  quality snow due to the high elevation(8500ft base-11000 peak),  an insane amount of sun,  and terrain that will give you a challenge without scaring the shit out of you.  and not to mention you can take a break in the main park and watch the best park skiing and snowboarding in the world.
but as for whistler,  wistler is the best inbounds skiing in north america,  the only downside is the lack of sun.
the problem with my choices is price,  both being the high end lift tickets.
if you cannot afford those options check,  kirkwood or mt. rose.
alot of people would not agree with me but i say steer clear of the rockies,   dry snow means rocks and sub zero temperatures.