If I only had time to go to one would you recommend that I go to a snowboard shop (powder and sun) or a big sport shop (sports basement, REI)?
A large shop will likely have a better selection of sale goods, but probably only from a big manufacturer. I went to Sport Chalet locally yesterday and they had some 2011/12 K2 boots for like 40-50 bucks on sale that retailed close to 200. Some bindings and boards on sick sales too but in weird sizes. Small shops will have a better selection I've found and better staff.