I'm looking to get a new full winter setup for my X5. Does anyone know what are some of the better snow tires for the X5? Also what about a place (web or otherwise) where I can find some reasonably priced OEM rims as well?

ebay

Try the TireRack.com

I'm running the stock 18's with Pirelli Scorp Ice and Snows. They are unstoppable! The abs gives up long before the tires. I'd recommend to anyone. Try Tire Rack and one of the BMW stores that discount wheels. You should be able to find 'em at 25% off list.

And . . . we DO get some snow around here - The Buffalo, NY area.

Good luck.