Don't get liferesripted's build.. Mine is similar I admit, but it includes a 7950 which is a MUCH better graphics card. I put this together a couple days ago for someone else.
Gonna be honest, that sale was not on when I put together the build. I will say that you should shoot for 8 gigs of ram though. And stay the hell away from the CX series of power supplies. The voltage ripple barely meets the acceptable standards, which is a little frightening when you think about it. The XFX i put in has much better voltage regulation, keeping your expensive parts safe from frying.
lol, didnt mean to hurt your feelings lol, but not getting a 7950 would be a horrible. Swapping out the PSU I agree on, and IF the 8 gb of ram is still in the budget, then definitely, but if you have to choose between 8 gigs of ram and a 7950, then get the more powerful graphics card.
4gb is fine for just games. 8gb is optimal for future proofing. Also asrock boards have the software to create a ram drive for temp files.. its really nice and fast.