Since we became engaged in Banff, we're pretty big fans of this mountain destination. We've both only visited the area in the winter, but I'm sure the summer there is awesome.
Banff Fairmont Springs Hotel, Banff National Park $$$
Brewster's Mountain Lodge, Banff National Park $$
Willow Stream at Banff Fairmont Springs (one of the best spa
experiences one could have!)
and another one