Thank you Landlady!
I go with studded tires, they increase the resistance a little but It´s better to be safe than sorry. I´m also trying to make myself as visible as possible as a biker is not as common in wintertime as in the summer, a fluorescent west, a rearlight on the bike and another one blinking on my helmet. A friend of mine drove past me in her car when I was the only one on the road ahead, she claimed that i looked like a rolling disco. Visibility-goal accomplished!
I only have one front light but that is usually enough since most of my focus goes to whats in front of me anyway. Always wear a helmet. Always.
Last winter (my first on a bike) the snow was only a few inches deep at most. The slush that thawed during the day to freeze at night was the hardest, just smooth snow or ice is ok. You will probably "crash" on one occasion or the other, I did and probably will again, but the snow, studded tires, lower pace and the fact that you wear more clothing in wintertime, helps to keep down the bruises to a minimum. What does that matter when you've got snow making that snowy sound under your bike and a gazillion stars above?