PowderKing wrote an answer about Northwave Snow Decade SL Snowboard Boot - Men's on November 19, 2012
I have a narrow foot, and used to have a hard time finding snowboard boots that fit me correctly and kept my heels locked in place. I would go the same size you wear in street shoes..... DON'T size up. I wear 10.5/11 in street shoes, and 11 in NW boots is too large. The 10.5 is perfect.