Which kind of shoes do you think are necessary for the winter, especially where it snows?

We're boring and practical over here, so I try to get by with as few pair of shoes as possible. Do you think kids need a pair of boots, in addition to their every day pair of tennis shoes?
I think I probably will need to get L a pair of boots since I would cringe if her tennis shoes got too wet/snowy/muddy. Favorite winter boots?