4 gb of ram? i would personally ditch 2 gb, save up a little, and use the money to SL-i two gtx's. now that would be sex. although i suppose its unneccesary since no game will be able to use that card to its full potential for a pretty long time. or use the money to up the power supply
only small bottleneck I see is hard drive. why dont you get a raptor 150? or better yet two 74 gb raptors and throw them in raid 0?