If you absolutely just wanted one set of tires, I'd recommend the All-Weather Nokian WR G2. It's an H (or V) rated Winter Tire that happens to not wear down in the summer time, thus why they can also offer a 30,000 mile warranty on it (for Mazda 5 sized tires, the higher profile tires hav 60,000 mile warranties). They are pricey, and they still aren't the best for snow or ice starting traction although they do stop very well in both conditions plus they have excellent resistance to hydroplaning and slushplaning. You are not going to find a set of all-seasons that perform better than these tires I guarantee that, but they're still a compromise. I had them for a bit and I liked them but my wife hated them and did not feel safe, so the tire retailer took them back and gave us Yokohama iG20s instead. They're not as good as the Michelin Xi2s but for the money they're great tires that'll provide three years of safe and solid winter driving.
