If you even think about riding on ice the is now way around studded tires.
On snow any decent tires with big knobbies will do. Snow will pack like mud, so a high front fender is a most. And it is very easy to get stuck parked on a snowdrift under the engine.
But a high center of gravity is not the best on winter roads, so a lower bike you can ride with two feet flat on the road might be worth a look
I rode my old xt600z all year round - the picture after i had to turn arround because i could'nt get trough the snowdrifts. Enstead i of the road i took it
across the fields where there was less snow.
The first picture on is 300km from - a long way home in that weather ...
http://www.motorcykelgalleri.dk/gall..._xt600z_tenere