Last winter we had a surprise cold front - surprised by time, not by existence. 1-2 inches was consequent of the ensuing storm; the wife had our little son and a poor handling ford ranger so I opted to ride home on my semi slicks (conti top contacts...awesome tires). The powder was mostly fresh and had fallen so quickly and unexpectedly that nothing was plowed. Took some steep hills with mini v brakes modulated by cross levers on 25c tires...that was fun! The only slippage had was trying to accelerate from a stop in low gear. The worst part was the winds - it was damn cold and I had to pedal so slow for the sake of traction that I never built up adequate body heat. I was nearly convulsing with chills by the time I got home, and the fingertip warmup was the most painful sensation I have ever experienced.
I've got studded rubber (as well as conti top contact winters) hanging in the garage this year! We're still hitting erratic highs during the week (nearly 60f today after 20f and snow yesterday) so I'll keep the slicks on for now.