Check out REI's regular site and their outlet. You just missed it, but they do a super clearance twice a year (Feb and Aug). Stuff is usually around 60-80% off. I pick up some amazing deals every time.
EDCDepot.com has some neat stuff as well, and some good prices for a small operation. They have a 10% off coupon with code SEPT going right now.
Sierra Trading Post is always one of my favorites. They do sales on each category pretty regularly, so if you combine the sale with one of the 20% off coupons that they always have, you can get some amazing deals.
Campmor used to be pretty good, but I have not seen any great deals there in a while. If you can't find the stuff cheaper elsewhere, they are still a good place to shop. Good people and great customer service.
I have spent many thousands of dollars at steepandcheap.com. It is like a never-ending REI super clearance. It is especially great for technical clothing, which a lot of people underestimate the value of.
I have spent a lot of money at all the above stores. Maybe one of these days I'll put up a page on my site about all of the outdoor gear stores.