For me, the biggest reason I don't ride in the winter is the bike paths aren't cleared and the snow banks crowd me too far into the streets where the vehicle operators with their faces glued to their phones aren't expecting anyone on a bike. That and I can't easily clean off the super fine grit winter riding accumulates indoors without having to then clean it off everything else.
I highly recommend snow tires—my highish-powered FWD car is like a rally car with them (and my low-powered one before it was a tank). You can often find sets with lightly used winter tires for pretty cheap on craigslist. Got my friend a set of mounted Blizzaks nearly new for $400 for her Maxima (the tires alone are usually more than that, never mind the wheels and balancing). Of course, you have to have a place to store them.