I might build this DX10 setup: 
 
Case: 
Coolmax CS-480-Black Mid Tower Case (Black) Retail 25$ AR 
 
Power Supply: 
Antec True Power Trio 550W Power Supply with Three 12V Rails $75 AR 
 
Motherboard: 
MSI P6N SLI-FI LGA 775 NVIDIA nForce 650i SLI ATX $121 
 
CPU: 
Core 2 Duo E4300 (Easily Overclocks to = E6400 with stock cooling) $117 
 
Hard Drive: 
Maxtor 160GB SATA $40 
 
Memory: 
OCZ 2GB (2x1GB) DDR2 PC2-6400 Platinum $112 AR 
 
Video Card: 
EVGA GeForce 8800GTS  $266 
 
 
Comes out to be a little more than half the price of your comp.  Gotta find those good deals :) 
                
                
                
                
        
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