Im doing a build around $900 before MIR and Promo discounts. Here's what i've come up with http://pcpartpicker.com/user/Killerfrenzy96/saved/1Rk1. I don't plan to crossfire so 650w is fine. I have a old Segate Barrucuda 1TB HDD with Windows 7 64-Bit on it.
Looks great!
The ONLY thing I would change is the RAM, to something physically lower profile, like G.SKILL Ripjaws X, but other than that, you hit it on the nose.
MIght want to invest in a CPU cooler, or SSD. They can be added later.