What you did is very similar to my setup, only I wanted an actual replacement/gaming PC as well.

Here's what I bought on NewEgg:
     1   
DISCOUNT FOR COMBO #642427
-$40.00
     1   
AMD Phenom II X4 965 Black Edition Deneb 3.4GHz Socket AM3 125W Quad-Core Processor HDZ965FBGMBOX
Item #: N82E16819103727
$140.99
     1   
Thermaltake TR2 TRX-1200M 1200W ATX 12V v2.3 / EPS 12V v2.91 80 PLUS Certified Modular Active PFC Power Supply
Item #: N82E16817153119
$229.99
     1   
ASUS M4A88TD-V EVO/USB3 AM3 AMD 880G SATA 6Gb/s USB 3.0 HDMI ATX AMD Motherboard
Item #: N82E16813131646
$119.99
     1   
Antec Three Hundred Black Steel ATX Mid Tower Computer Case
Item #: N82E16811129042
$59.95
     2   
G.SKILL Ripjaws Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666) Desktop Memory Model F3-10666CL9D-8GBRL
Item #: N82E16820231311
$169.98
($84.99 ea)
     1   
ASUS DRW-24B1ST/BLK/B/AS Black SATA 24X DVD Burner - Bulk - OEM
Item #: N82E16827135204
$20.99

Subtotal   $701.89
Tax   $0.00
 UPS 3 DAYS   $13.45
Order Total   $715.34

I then got two cards on Amazon: (Currently Out-of-Stock)
http://www.amazon.com/Sapphire-Radeon-PCI-Express-Graphics-100282XTREME/dp/B004W75ATI/ref=sr_1_1?ie=UTF8&qid=1306812248&sr=8-1

If you do this, you will need to purchase a CrossfireX Bridge as well:
http://www.amazon.com/gp/product/B000PD81LW

Also, I recently have this being shipped to me to make sure I'm using my PSU efficiently:
http://www.amazon.com/gp/product/B00009MDBU

EDIT: My only comment on your build specifically would be whether or not you really want to get a Full Tower Case.

ALSO, I almost forgot this sucker:
http://www.amazon.com/Antec-Cyclone-Blower-Case-Expansion/dp/B000051299/ref=sr_1_1?ie=UTF8&qid=1306813611&sr=8-1