I just have a "normal"(?) all-weather biking jacket (gore-tex or some similar material). For pants, I'm not into spandex tights (which seems all the rage these

I just have a "normal"(?) all-weather biking jacket (gore-tex or some similar material). For pants, I'm not into spandex tights (which seems all the rage these days), so I just have a pair of "out-doorsy" pants of some similar material as the jacket. If it's cold, I just put more layers underneath. For the undermost layer, it's worth to use these "technical" underwear, as you'll freeze like heck once you start sweating if you use cotton underwear. I find that I manage with surprisingly little clothes even if it's cold, the main thing is to be covered up so that the cold outside air doesn't enter from sleeves etc. Aside from that, the most critical for me is shoes and gloves, I easily start freezing my toes even though I'm otherwise Ok. And if it's colder than, say, around -15C, some kind of face mask and glasses are good, otherwise your face freezes. As for equipment, I have winter tires for my bike. I haven't bothered to acquire another pair of wheels, I just change the tires in the autumn and spring. My winter tires aren't any wider than my summer tires, so it gets a bit tedious if there's loose snow on the path. Most of the time it's fine, though. I don't have a separate "winter bike", I use the same bike both summer and winter (a cyclocross/touring kind of thing with drop handlebars etc.).