there seem to be two schools of thought to winter tires: studded and skinny. studded tires can grip ice very well though tend to lose traction in deep snow and packed, rutted snow. While skinny tires slice through everything except black ice.
I need a winter bike that can double as a rain bike. A couple days in the rain and my rear wheel is thick with road and brake grime. I dislike having to take the time to wipe my bike down incessantly. It receives enough of my attention as it is.