In reply to myrockface:
I lived in Banff for a year in 1997 (yes I know it was a long time ago). I also lived in Lake Louise for two months.
The biggest mountaineering community is likely to be in Canmore. This is because it is just outside the national park. Accommodation options within the park are quite limited. Often apartments are tied to employers. The people you meet will tend to be transient in nature. You are likely to meet more long termers and more reliable / experienced climbing partners in Canmore.
Having said this it does not have a ski hill going into it. Banff has a relatively small resort nearby but most skiers travel by bus from Banff to Lake Louise or Sunshine village.
I did visit Jasper in summer. It is pretty small but is likely to have a small but very active scene.
The other option is Whister. I have never been. I have heard very good things. Especially for mountain biking, skiing and climbing.
However, I think the reality is that there is nowhere like Chamonix in Canada. The vibe is going to be very different.