I'm going to be running 5 monitors and doing some pretty intense multitasking with databases and lots of stuff open at once. I did a good amount of research and my main uncertainties are the points that I starred below.
CPU $290
Intel Core i7 2.66GHz
http://www.newegg.com/Product/Product.aspx?Item=N82E16819115202
CPU Cooler $70
Cooler Master V8
http://www.newegg.com/Product/Product.aspx?Item=N82E16835103055
Hard Drive (2) $200*2=$400
Western Digital VelociRaptor 300GB
http://www.newegg.com/Product/Product.aspx?Item=N82E16822136322
Case $260
Silverstone TJ09
http://www.newegg.com/Product/Product.aspx?Item=N82E16811163073
DVD Drive $30
HP DVD-RW
http://www.newegg.com/Product/Product.aspx?Item=N82E16827140031
Power Supply $250
Antec Signature SG850 850W
http://www.newegg.com/Product/Product.aspx?Item=N82E16817371018
Operating System $100
Windows Vista Home Premium 64-bit
http://www.newegg.com/Product/Product.aspx?Item=N82E16832116488
Memory (2) $136*2=$272
G.SKill 6GB (3 x 2GB) SDRAM DDR3 1600 (PC3 12800)
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231225
Motherboard $300
ASUS P6T Deluxe
http://www.newegg.com/Product/Product.aspx?Item=N82E16813131346
Graphics Cards (3) $145*3=$435
Sapphire Radeon HD 4850 512MB
http://www.newegg.com/Product/Product.aspx?Item=N82E16814102770
Sapphire Radeon HD 4850 1GB
http://www.newegg.com/Product/Product.aspx?Item=N82E16814102802
Sapphire Radeon HD 4870 1GB
http://www.newegg.com/Product/Product.aspx?Item=N82E16814102801
*Not sure on these. 4870 is so huge might be too big to fit 3 in the mobo?
Sound Card $0
HT Omega Claro Plus
From current computer
CPU $290
Intel Core i7 2.66GHz
http://www.newegg.com/Product/Product.aspx?Item=N82E16819115202
CPU Cooler $70
Cooler Master V8
http://www.newegg.com/Product/Product.aspx?Item=N82E16835103055
Hard Drive (2) $200*2=$400
Western Digital VelociRaptor 300GB
http://www.newegg.com/Product/Product.aspx?Item=N82E16822136322
Case $260
Silverstone TJ09
http://www.newegg.com/Product/Product.aspx?Item=N82E16811163073
DVD Drive $30
HP DVD-RW
http://www.newegg.com/Product/Product.aspx?Item=N82E16827140031
Power Supply $250
Antec Signature SG850 850W
http://www.newegg.com/Product/Product.aspx?Item=N82E16817371018
Operating System $100
Windows Vista Home Premium 64-bit
http://www.newegg.com/Product/Product.aspx?Item=N82E16832116488
Memory (2) $136*2=$272
G.SKill 6GB (3 x 2GB) SDRAM DDR3 1600 (PC3 12800)
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231225
Motherboard $300
ASUS P6T Deluxe
http://www.newegg.com/Product/Product.aspx?Item=N82E16813131346
Graphics Cards (3) $145*3=$435
Sapphire Radeon HD 4850 512MB
http://www.newegg.com/Product/Product.aspx?Item=N82E16814102770
Sapphire Radeon HD 4850 1GB
http://www.newegg.com/Product/Product.aspx?Item=N82E16814102802
Sapphire Radeon HD 4870 1GB
http://www.newegg.com/Product/Product.aspx?Item=N82E16814102801
*Not sure on these. 4870 is so huge might be too big to fit 3 in the mobo?
Sound Card $0
HT Omega Claro Plus
From current computer