I boot around in our famously fun upstate New York winters on a set of BFG Winter Slaloms, and they do a pretty credible job.
Last November, I drove to the tire shop on my BFG KDW's to swap them for the Winter Slaloms. As coincidence would have it, we got our first snow of the year the previous night - about 3" of snow - and I slipped and slid the 1/2 mile or so to the tire shop.
Conclusion: Dedicated snow tires are highly, highly advisable. I suppose you could get all seasons, but if you already have a good set of high-performance summer tires, why would you even bother with all-seasons for winter driving?
