Nick - 15's are probably about a size 13-13.5 military boot. I wear size 13 shoes and a size 11.5 military boot. I wouldn't mail order anything until you find out what size boot you need.

Ohio is looking GREAT! I never saw any insane winters like that when I lived there.

Poly Pro is as Mac said part of the ECWS (extreme cold weather system) that the military uses - its a fiber pile polypropylene, and it moves sweat away from your skin. Its supposed to be used in conjunction with a goretex jacket/pants, which also wick moisture away and is relatively windproof. Wool socks act the same as fiberpile. Cotton retains and absorbs moisture, which is pretty dangerous if you're cold. Sweating when you exert yourself and then cooling off will lead to hypothermia very quickly. The other key is to wear loose layers of clothing - the space between layers holds body heat and keeps you warmer. You want your winter boots to fit more loosely than regular boots or jungle boots. This is all garbage that the Army stuffed in my head, but its all very true. We'd spend weeks in the field in Korea during the winter - boy was it cold! Another thing I learned very quickly was not to keep my head inside of the sleeping bag - breath -> moisture -> wet -> freezing. I'd wear a Balaclava over my head and leave it outside of the bag, even in negative temp weather (usually would add a stocking cap and neck gaiter over top of the balaclava as well).