Spent about 2-3 months gathering up gear for this season as i just started to get into snowboarding seriously.
Main places i go to shop you have already mentioned others:
REI: Outdoor Gear, Equipment & Clothing for Camping, Hiking, Cycling, Fitness, Kayaking, Canoeing and More
Tactics Board Shop: Snowboard / Skate / Surf / Clothing / Gear
Skis, Snowboards, Wakeboards, and Apparel | evo
Altrec.com - The North Face, Patagonia, Backpacks, Shoes, Board Shorts, Camping Equipment
<=== don't know the correct spelling but its around there.
eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices
for stuff that can't be shipped out of the US. *cough*burton*cough*
Buzzillions.com product reviews - Get the Buzz before you buy!
=> for non-biased user reviews on items
Reviews from Epinions
=> searches online stores for an item you want.
I'm very careful when making purchases online so i do a bit of research before i commit to an item.