Bogs Classic High Handles boots >> $120
When it comes to warm and waterproof, Bogs did everything right. The muddier cyclocross gets, the more time you spend pitting for your friends or washing down your bike before and after races. A couple years ago, everyone I knew who pitted for their friends and spouses had a pair of rain boots and froze every fiber of their feet. Enter Bogs.
Classic High Handles Women's models are fully waterproof and comfort rated for temperatures down to -40 degrees, and while I haven't tested them in those conditions, I fully believe that they are up to it. They are heavy-duty, but also available with fun flare fitting of cyclocross. And putting handles on boots was a stroke of absolute brilliance.