If you have the room to store them, having a dedicated set of winter wheels/tires is the way to go. It might cost more initially, but you get back most of the investment by keeping the mileage off of your summer tires, meaning you won't have to buy summers as frequently. Plus you'll be kicking yourself when you try to pull 0.9g+ on all-seasons in the summer.
Mine: 2008 Saab 9-3 Aero SportCombi XWD: 82k, Black, MANUAL
Gone: 2002 SVT, #1654
Hers: 2010 Focus SES: 70k, Ebony, Auto, Moon and Tune