Most of the time I use my regular MTB shoes (Shimano MO36). For temperatures below freezing, with snow, I have a pair of Shimano FR80 a size larger than normal. They may have discontinued that model, they are all leather with a padded ankle. The extra size gives me room to wear Seal Skinz or hytrel socks over my wool socks. Works down to 5 degrees F. If I encounter colder I'll update. Lake has some shoe-boots that look promising, so does Gaerne (sp?), and I think I saw some Northwave shoes with neoprene liners at sierratradingpost.com.