Yes, a lot of people run 19s or even 18s in the winter, as running summer tires in cold temps is downright scary since they pretty much turn to cement blocks in temps below 40 degrees.
If you're looking for a second set of wheels for Winter, I will shamelessly promote myself right now as I have a set of OEM 19s with all-season tires currently for sale.
http://www.xbimmers.com/forums/showthread.php?t=939169 I ran these for about 1000 miles this winter, and they did really well in the snow.
Good luck!