If you don't have the upgraded brakes, I would run 17x7.5 wheels all around with 225/50x17 tires. If you really want to run 18" or have the larger brakes and need to, run 18X8 with 225/45x18.
The whole point of running snow tires is to get the best snow and ice traction. I don't see a point in sacrificing snow and ice performance to run something that looks better. Besides, they don't need to be on the car that long anyway and the car is always dirty in the winter, so it never looks good until the salt is gone.
Makes me appreciate my summer set even more when they go back on.
