Take a look at this:
CyberPower Gamer Infinity 8800 Pro SE
$1,500 retail
Here are the Specs:
CASE: NEW!!! CoolerMaster Cosmos S Gaming Full Tower 420W Case w/ Transparent Side Panel
CPU: (Sckt775)Intel® Core™ 2 Duo E8400 CPU @ 3.0GHz 1333FSB 6MB L2 Cache 64-bit
MOTHERBOARD: (QX9650 Support) Asus P5N-D nForce 750i SLI Chipset LGA775 FSB1333 DDR2 Mainboard
MEMORY: (Req.DDR2 MainBoard)2GB (2x1GB) PC6400 DDR2/800 Dual Channel Memory (Corsair or Major Brand)
VIDEO CARD: NVIDIA GeForce 8800 GT 512MB 16X PCI Express (Major Brand Powered by NVIDIA)
VIDEO CARD 2: NONE
VIDEO CARD 3: NONE
LCD Monitor: 22" TFT Active Matrix LCD Display (Generic 22inch WSXGA TFT LCD Display)
HARD DRIVE: Single Hard Drive (500GB SATA-II 3.0Gb/s 16MB Cache 7200RPM HDD)
Data Hard Drive: NONE
Optical Drive: (Special Price) LG 20X DVD±R/±RW + CD-R/RW DRIVE DUAL LAYER (BLACK COLOR)
Optical Drive 2: 16X DVD ROM (BLACK COLOR)
SOUND: HIGH DEFINITION ON-BOARD 7.1 AUDIO
I like Thermaltake cases myself. I have a Tsunami
I definitely agree with an Asus Motherboard, but probably go with an Athlon Processor. I have NVIDIA myself, although not that high end of a card as the above system because I don't do gaming.
As for the hard drives, consider a couple of WD 150 Gig Raptors running in RAID 0 for optimum speed. Just make sure you keep it backed up.
I installed a water cooling system in my computer because I bought the Pentium D Dual Core when it first came out and the thing ran too hot--they've since improved the heat issues, but water cooling is great because you can keep a much quieter computer. I installed a Swift Tech system in Mine. Below is a review of 7 systems at Tom's Hardware--I linke to the conclusion page.
Conclusion - Tom's Hardware : 7 Hot New Water Cooling Systems Tested