Pirelli makes a tire called the "Winter Asymetrico" that is basically a mixture of the blizzak type compound and soft rubber. Traction is incredible and consistent and they were the best tires I ever drove through a MN winter on my Miata. If you're looking strictly for a winter tire that you will absolutely replace in the spring, I would recommend these. They are MUCH better on dry pavement than the blizzaks and we all know that most winter days DO have dry pavement.
If you want a tire that performs well in the snow AND performs well in the heat (all terrain tire) that won't "humm" or "buzz" on dry pavement, choose the BFG ATs or the Pirelli Scorpions. The Pirellis have a higher snow rating which is why I chose them, the BFGs are a 3 ply tire and are vastly superior in rocky terrain.
The stock tires are "OK" for most situations but definately not spectacular for any one in particular. Where do you drive? How many miles per day? How do you drive? Do you drive in lots of traffic or on open country roads, etc... these are the questions you have to consider before you buy tires.
If you go to the trouble to spend the $$ for tires that are "Specifically designed for winter" then you compromise your ride comfort and safety during those sunny, dry winter days. Its my opinion that if you're gonna spend $$ for tires, get one that will perform better on any surface than the stock Grabbers. FWIW, Blizzaks, duelers, and other "pure snow" tires are rated better than good all-terain tires on "pure glare ice" and "pure packed snow" conditions only. How often do you drive in those conditions?
If you drive your kids across a frozen lake to school everyday, get the blizzaks. If you live in the country and they don't plow the roads very often, get the asymetricos. If you want to get around much better than stock in the rain, snow, mud, or pavement, get the Scorpions or the BFG ATs. If you want to learn more about tires, tread compound, rating, testing, etc, go to
www.Tirerack.com.