I built my new PC last month...unfortunately, it *is* a "Crysis face melter" (great line BTW
)and would not fit into the budget you mentioned. What I can say is that, if you intend to network this computer to another at your place, I would recommend as an OS getting Vista Business or Ultimate instead of the Home Premium version. If this is to be your only computer, then Home Premium would be ok.
Despite the online critcisms against it, I find that I really like Vista. While I wish I had gotten Ultimate now (I opted for Premium), it's not really a showstopper in connecting to the wife's computer, but I just wish I had some of the tools that it has. It was also quite simply the easiest OS installation I've done.
As for the hardware, as always get the best Quad CPU you can afford, and maximize your RAM (4GB if a 32bit OS, as much as you can if 64bit). Almost all motherboards have a PCIE slot so you can upgrade your video card in the future. Oh, and like you, Newegg was my only supplier!
Just my $.02, report back and let us know what you wind up going with!