I'd say continental topcontact winter, except the narrowest it comes is a 37. No studs, but a winter rubber compound - just like we use on cars. I actually like to have 2 bikes on the go - even faster than wheelsets, and you can still ride the next day if you don't have time to fix a mechanical.

I ride schwalbe winters (2 rows of studs), but my commute is only about 18km each way. Much further and I'd be considering a no-stud option.