+1 on Nokians and the Schwalbe studded---either will do the trick very well. it's just cool as hell to hear the "chatter" and "rumbling" of the studs on pavement. and it's even cooler to not hear them when you cross sheets of ice (and still remain upright). but as peter white admonishes his readers: don't let the tires give you overconfidence!... when you get off your bike your shoes aren't studded.