I was just browsing a bit on newegg.com. Here's a quikcy I just threw in:
Core 2 Quad E6600 (4x 2.4GHz)
Asus P5K Motherboard
2x 1GB G.SKILL 1066MHz High performance RAM (PC2 8500)
2x 250GB Samsung Spinpoint (SATA-II, 3.0Gb/s)
GeForce 6200LE (64MB, since there is no onboard video, 19$ card)
ATX case with a 225mm ventilator in the side, 450W power supply
Total 604.93$
If you have an old PCIex16 video card lying around you can remove the video card.
Doubling the memory (4x 1GB will bring it to 680$)
This is without shipping, since you need to enter your zip code
Core 2 Quad E6600 (4x 2.4GHz)
Asus P5K Motherboard
2x 1GB G.SKILL 1066MHz High performance RAM (PC2 8500)
2x 250GB Samsung Spinpoint (SATA-II, 3.0Gb/s)
GeForce 6200LE (64MB, since there is no onboard video, 19$ card)
ATX case with a 225mm ventilator in the side, 450W power supply
Total 604.93$
If you have an old PCIex16 video card lying around you can remove the video card.
Doubling the memory (4x 1GB will bring it to 680$)
This is without shipping, since you need to enter your zip code

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