Nightlife in the Rockies is quite varied, depending on your intentions. Every
town has its set of pubs (due in part to the strong British traditions in
Canada) as well as its rock 'n' roll bars with live bands, and even a handful of
discotheques with recorded music and dancing. Notwithstanding the recent
Rolling Stones magazine about Banff's "wild side", which was not only was way off
base but wildly inaccurate, you can have a safe good time.
Most of Canmore's action is right in the "downtown" core, with a fair bit also happening in the thick of "motel row". Banff's activity is concentrated along the core of Banff Avenue in the downtown area ("under 400" Banff Ave). There are four other clusters, along Banff Ave toward the Transportation-Canada highway ("above 400"), along Caribou Ave toward the train station and Mount Norquay, across the River around the Banff Springs, and up the hill along Tunnel Mountain. There is lots of variety to be found here (just keep your eye our for the crowds). By contrast, Jasper's nightlife is pretty quiet, and Lake Louise's is relaxed (too sedate for the young crowd) but very well suited to the rich and ueber-rich from Europe and the US.
Heading over to BC, there's a lot happening there...Radium / Invermere / Windermere has a number of establishments catering to the skiers in winter, and the waterskiers in summer who spend their weekends or their summer/winter season in this playground for the Calgary rich. Golden and Revelstoke on the Transportation-Canada get a lot of drive-though traffic (not the kind to drink and party much--thank goodness) but these towns also attract the heavy-into-recreation set That in summer are hiking and mountain biking and in winter are downhill, cross-country of heli-skiing. Play hard, drink hard seems to tbe tehir motto, and there are plenty of pub-style establishments in town to keep those folks happy. Kimberley, further south and off the Transportation-Canada is also a year-round recreation centre, with a few good places to party in town. The locals there often head south a tad to (or at least towards) Cranbrook, which is the south-east BC's major economic and industrial hub. And heading east a bit, the town of Fernie has a humming pub & club scene especially during the winter ski season, when Fernie's slopes seem to attract more snow than anywhere outsideof BC's "Lower Mainland" (and much more fluffy snow, period!)
Of course, if you are drinking, don't drive...take a taxi or stay in a hotel or motel close to the nightlife if that is your aim.