I've considered previous comments and modified the list a bit.

Motherboard & CPU:
GIGABYTE GA-EP43-UD3L LGA 775 Intel P43 ATX Intel
Motherboard - Retail
+
Intel Core2 Duo E7500 Wolfdale 2.93GHz LGA 775 65W
Dual-Core Processor Model BX80571E7500 - Retail
= $185
http://www.newegg.com/Product/ComboD...t=Combo.253271

RAM:
Patriot Viper II 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2
1066 (PC2 8500) Desktop Memory w/Futuremark 3DMark Vantage Bundle Model
PV224G8500ELKB - Retail
$69
http://www.newegg.com/Product/Produc...82E16820220426

Power Supply:
BFG Tech GS-550 550W ATX12V V2.2 / EPS12V V2.8 SLI Ready
CrossFire Ready Power Supply - Retail
$50
http://www.newegg.com/Product/Produc...82E16817702010

Add in the same case that I mentioned before and the grand total,
including taxes and shipping, comes
to $478, minus a $40 mail-in rebate.

How's that look?