I was thinking about the following for a sub-$500 quad crunching rig. The only things missing are a cpu f/hs and a case. But I've got stock fans I could use and the case should be something creative. I don't know if I'm going to do it, but I'd like to hear ideas and suggestions. Let me know if you think it should go in it's own thread.

Athena Power AP-MP4ATX40 MicroATX 400W Power Supply - Retail
WINTEC AMPO 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit
Open Box: GIGABYTE GA-G31MX-S2 LGA 775 Intel G31 Micro ATX Intel Motherboard
Intel Core 2 Quad Q6600 Kentsfield 2.4GHz LGA 775 Processor Model HH80562PH0568M - OEM
SYBA SY-IDE2SDMMC IDE to SD/MMC Adapter - Retail
A-DATA Turbo 8GB Secure Digital High-Capacity(SDHC) Flash Card Model TurboSD SDHC 8G -