I went the route of finding a sweet deal on a used set of OEM 18" with TPS, and I had winter performance tires (Dunlop SP Wintersport 3D) mounted on them. I find it a PITA to get back and forth to the tire store for mounting, so this way I can do the swap myself.
The weather around here is unpredictable. I have a couple snow cars that I use if I know there will be snow on the ground. But I also like to be able to drive my coupe and not worry about whether I'll get home if the snow comes in earlier than they forecast. My neighbor has a RWD 328i coupe with all-season radials, and a couple of times a winter (at least) she gets stranded somewhere on the way home from work if it snows more than an inch.
Unfortunately, nothing sticks in the winter as well as summer tires in the summer. But I feel more secure on winter tires than I would on summers. My other RWD BMW coupe (a 79) has summer Pirellis on it, and if I try to drive it in the winter, the back end breaks out like CRAZY.
Sure, I could drive on summer tires in the winter and "take it easy," but what I worry about is an emergency caused by some other driver, where I need grip for a short stopping distance or a fast lane change. For me, it's worth the hassle of maintaining two sets of wheels.
BUT to each his or her own, I always say.