Newegg has an MSI TwinFrozer GTX 670 for $409.00 after rebate...I just bought one, it out performs the ATI/AMD card, and it's a lot less cash right now, it was hard for me to make the switch, I tend to like ATI a bit better, but the performance/$$ is something I couldn't pass up.
Do you have a MicroCenter where you live? They sell that CPU for 189.00, and the motherboards are about the same price, but when you buy mobo and CPU...you get another $50 off....that's a pretty big saving over Newegg. The only catch is that it's in store pick up only. I just bought my mobo and CPU there, and bought the rest from Newegg.
I know that your video card is only $329...but if you can do the Micro Center deal, the savings would allow you to step up to the 670 without going over budget.
Looks like you will have a pretty kick arse machine!