Building a gaming rig

Im very close to ordering the parts I need for my new computer and I just want to make sure I maximize performance/cost. Here are the parts I want to include in my computer.

PLEASE READ: I would appreciate if anyone could tell me if any of these parts will be "replaced soon" (ex. 7900GTX->8800GTX) I know that nvidia is supposed to be coming out with a 9900 series or something but I dont think ill be needing them for a while.Whatever is not on the list I have the parts at home from another computer.

Processor- Intel Core 2 Quad Q6600 Kentsfield 2.4GHz

http://www.newegg.com/product/product.asp?item=N82E16819115017

Motherboard- EVGA 122-CK-NF66-T1 LGA 775 NVIDIA nForce 650i Ultra ATX Intel Motherboard

http://www.newegg.com/product/product.asp?item=N82E16813188017

Power Supply- CORSAIR CMPSU-520HX ATX12V v2.2 and EPS12V 2.91 520W Power Supply

http://www.newegg.com/product/product.asp?item=N82E16817139001

Case- Antec Nine Hundred Black Steel ATX Mid Tower Computer Case

http://www.newegg.com/product/product.asp?item=N82E16811129021

Operating System- Microsoft Windows Vista 64-Bit Ultimate for System Builders

http://www.newegg.com/product/product.asp?item=N82E16832116215

Monitor- CHIMEI CMV 221D-NBC Black 22" 5ms DVI Widescreen LCD Monitor 330 cd/m2 800:1

http://www.gamespot.com/pages/forums/post_msg.php?board_id=314159272

These are all the things I will be buying for my computer. I have 2 gigs of ram/sound card/video card(8800gts)/harddrive/keyboard/mouse/speakers.