Whistler is regarded as the top resort but if you're there in Feb 09 the Olympics will be just around the corner so it could be a bit of a building site...
I've been to Banff many times (used to live a few hours away) and that is a fantastic place to stay. Loads of pubs/nightlife and it's really beautiful too. There's easy access to 3 ski areas (Norquay, Sunshine and Lake Louise), with jouney times of approx 15min, 40min & 70min respectively. A tri area lift pass including bus pass is about $85 per day. The best resort of the 3 being Lake Louise. Norquay is quite small and you'll quickly get bored, although they do have a pretty awesome jump/rail park there (Lake Louise has removed all their jump park as they feel it's too dangerous).
Another place to consider is Jasper, again very senic and there's a few places to keep you busy in the evenings. The hotels/lift pass would probably be a bit cheaper here then in Banff. The ski hill isn't huge, but would keep you busy for a week easily and it's pretty varied ability wise so you wouldn't have any problems regards this. The times i've been here I've noticed the snow feels much much nicer to ride on then any other resort i've been to.
Other popular resorts with Canadians are Fernie and Kicking Horse. Fernie is worth a look as they always have far more snow then any of the other resorts in the area and I've only ever heard great things about the place.
If you're going in school holiday season it might be better to avoid the Banff areas as the resorts around here get pretty crowded. Although with the areas being so huge it's not a big deal.
