I'm sure many of you are members of GCR, but they only offer 0.75% cashback when you buy at the Apple Store.
I just came across this site, Pigsback, where the rebate for Apple Store purchases is 2%, mind you, not cash but gift cards and some merchandize. But the gift cards are from common places so it's as good as cash in my mind.
Pigsback.com - You get more back with Pigsback.com - 0