He's from New York... I'd strongly recommend you build yourself. Use whatever you can save from your computer now and save fuckloads of money. If you can save your case, a floppy, a cd/dvd burner, power supply, maybe even motherboard, all you're looking at is CPU, GPU and some RAM, you could only spend about $400 and end up with good shit... depends man. Pre-built computers are fuckin stupid expensive for what you get. All I'm seeing (at least over here) are $700 Pentium 4's or E-series duo cores, which are shit for that kind of money...
Worst comes to worst, save your money, and spend $800-$1000 on a pre-built that comes with the latest shit... Any lower than that (price wise), and you're getting screwed with old/shit parts...