Two weeks ago, Circuit City had a promotion that if you bought 1600 points and any game over $30, you would get $10 back.
I used it to buy halo 3, which then went on sale the following week at Target, so I got the Circuit City promotion plus the pricematch at Target the following week.
Obviously, the sales are over now, but I would keep an eye out in the sunday paper ads for future deals at perhaps Circuit City, Best Buy, or Target. Good luck hunting!
PS you might also want to watch for deals on ebay.