how is this build?

1 LITE-ON Combo Black SATA Model DH-52C2S-04 - OEM
Item #: N82E16827106100
Return Policy: Standard Return Policy
Select An Optional Extended Warranty Plan 1 Year Extended Service Net Replacement Plan -- $9.992 Year Extended Service Net Replacement Plan -- $14.99
$22.99
1 COOLER MASTER RC-690-KKN1-GP Black SECC/ ABS ATX Mid Tower Computer Case - Retail
Item #: N82E16811119137
Return Policy: Standard Return Policy
$84.99
1 Seagate Barracuda 7200.11 ST3500320AS 500GB 7200 RPM SATA 3.0Gb/s Hard Drive - OEM
Item #: N82E16822148288
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Select An Optional Extended Warranty Plan 1 Year Extended Service Net Replacement Plan -- $29.992 Year Extended Service Net Replacement Plan -- $39.99 -$10.00 Instant

$109.99
$99.99
2 EVGA 512-P3-N871-AR GeForce 9800 GTX(G92) 512MB 256-bit GDDR3 PCI Express 2.0 x16 HDCP Ready SLI Supported Video Card - Retail
Item #: N82E16814130339
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$619.98
$599.98
($299.99 each)
1 CORSAIR CMPSU-620HX ATX12V v2.2 and EPS12V 2.91 620W Power Supply - Retail
Item #: N82E16817139002
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$25.00 Mail-in Rebate
$189.99
$169.99
1 G.SKILL 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 1066 (PC2 8500) Dual Channel Kit Desktop Memory Model F2-8500CL5D-4GBPK - Retail
Item #: N82E16820231166
Return Policy: Memory (Modules, USB) Return Policy
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$184.99
$144.99
1 EVGA 123-YW-E175-A1 LGA 775 NVIDIA nForce 750i FTW SLI ATX Intel Motherboard - Retail
Item #: N82E16813188026
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$189.99
1 Intel Core 2 Duo E8400 Wolfdale 3.0GHz LGA 775 65W Dual-Core Processor Model BX80570E8400 - Retail
Item #: N82E16819115037
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$209.99
1 COOLER MASTER RR-CCZ-LL12-GP 66mm Sleeve CPU Cooler - Retail
Item #: N82E16835103042
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$44.99
Subtotal: $1,567.90

If you don't plan on OC'ing the E8400 much that CM Sphere cpu cooler will be all right. It's about a middle of the road on CPU cooling and overclocking performance. HardwareLogic review http://hardwarelogic.com/news/137/ [...] 10-24.html

The rest of your choices are well thought out and should give you excellent gaming performance.
Noted the 2x 9800GTX GPUs. We're all assuming you have a good 1920x1200 24" LCD monitor?

The video card accessory pack has you covered.

It has two Molex-PCI-e power cable adapters to take care of the required 4 PCI-e power inputs.
And you should be OK to total system requirements. 9800GTX power requirements are about the same as the 8800GTS. Your total power draw under load should be under 500watts even with an OC'd E8400.
Going to go for max OC'ing on your CPU and both GPUs? Then we should talk some more.

Sorry; I wasnt the one that recommended a HD change.
Why do you need two 9800GTX? What monitor will you be using?

You shouldnt need TWO 9800GTXs to have smooth game play on a 22" 1680x1050 widescreen LCD. Start out with one 9800GTX and only get a 2nd if you find you cant get acceptable peformance with system. And then be sure it the GPU thats holding your system back and not some other component.