I have a commuter with rim brakes and a "good bike" with disk brakes. Used the good bike while the beater was being fixed up for a few weeks last winter, and totally messed it up in the snow and slush. We don't get extreme cold, but rain, snow and a lot of fluctuation around the freezing point. I'm keeping the good bike away from these conditions now. My main beef with disk brakes is that they're harder to fix, while I can troubleshoot and fix rim brakes with my eyes closed. My commuter just gets so much regular hard use that it has to be easy maintenance.
Winter riding is much less about badassery and much more about bundle-uppery. - malkin
1995 Kona Cinder Cone commuterFrankenbike/Selle Italia SLR Lady Gel Flow
2008 white Nakamura Summit Custom mtb/Terry Falcon X
2000 Schwinn Fastback Comp road bike/Specialized Jett