What I'd take:
Newegg.com - Intel Core 2 Quad Q6600 Kentsfield 2.4GHz 2 x 4MB L2 Cache LGA 775 Quad-Core Processor - Retail
Newegg.com - ENERMAX Uber Chakra ECA5001BS Silver Aluminum / Steel ATX Full Tower Computer Case - Retail (big, tool-free installation)
Newegg.com - SILVERSTONE ST50F ATX12V 500W Power Supply 100 - 240 V cUL, CE, TUV, CCC, FCC - Retail
Newegg.com - Western Digital Caviar SE16 WD5000AAKS 500GB 7200 RPM 16MB Cache SATA 3.0Gb/s Hard Drive - OEM (pretty much the same specs as the one you chose)
Newegg.com - GIGABYTE GA-P35-DS3L LGA 775 Intel P35 ATX All Solid Capacitor Intel Motherboard - Retail
Newegg.com - MSI N9600GT-T2D512 OC GeForce 9600GT 512MB 256-bit GDDR3 PCI Express 2.0 x16 HDCP Ready SLI Supported Video Card - Retail (same price, better known manufacturer, factory overclocked and comes with a game, The Witcher, included)
Newegg.com - A-DATA Value Series 4GB(2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory - Retail (the performance difference between CL5 and CL4 is not big, so I'd go for 4GB for only $5 more, it will soon be called for)
Total (before any rebates): $862.
Rebates are $20 for the graphics card, $10 for the PSU and $35 for the case.
EDIT: Whoops, the memory and the hard drive were wrong, now corrected.