I purchased the tires listed on the link below. This is my first year of winter cycling, so I don't claim to know what I'm doing.

http://www.modernbike.com/itemgroup.asp?IGPK=2126177347

Thanks for the answers. When I get the tires, I'll mount them immediately. Hey, I'm an old man trying to burn calories. Added resistance doesn't bother me a bit! :-)