What are you currently driving?
As everyone has already said, good, new, winter tires are the single best thing you can do for winter driving. As McP said, most cars on most roads will do fine with a good set of winter tires.
Note in my statement I said “new”. Worn down winter tires are no better than summer tires, and I’d rather have a set of all-season tires with plenty of tread than a set of worn out winter tires any day. Too many people think that because they have winter tires on they’re fine, even though the tires are almost completely worn out.
In short, the condition of the tires are as important as the type.