I would go with a square 18" setup such as 225/40/18 with offsets in the ET35 ish range. Wide winder tires actually reduce deep snow traction (think snowshoe analogy) plus you can rotate them which helps conserve tire life as you will burn through your rears much quicker than the fronts.
If you are concerned with looks I would source out a set of wheel spacers to flush up the rears because a square setup will most likely have your rears sit well inside the wheel arch, which looks like CRAP.
To answer your original question i would stay away from so called "performance" snows tires. These tires sacrifice snow traction for cold pavement grip. The purpose of snow tires is to handle actual snow and when it inevitably arrives in Calgary I would want to know I had the best "snow" tires.
Any of these would be a start:
http://www.tirerack.com/tires/tests/...y.jsp?ttid=135