OK Here is a config,I suggest is a powerful gaming rig...
Processor:Core 2 Quad Q9550(2.83 Ghz) (350$)
Motherbosrd:Asus P5Q-E (200$)
RAM:1x4GB DDR2 800 (80-100$)
Graphics Card:ZOTAX GTX 280(Usies nvidia card zotax is the coling solution) (600$)
HDD:Seagate 500GBx2 (120$)
Monitor:LG 246Wp (24" widescreen) (480$)
Cabinet+PSU:CM 690 + Corsair TX 750 (200$)
This config will cost you about 2000-2100 US$(approx)
You can add more RAM to increase the performance like an additional 4GB stick for about 80US$.
EDIT: You can choose a DDR3 RAM but it is way to pricey now.In a few months it will become shit cheap tough.
Also another motherboard suggestion: ASUS Striker 2 NSE(400-450$)
PS: Do consult some technician also.
Last edited by AKP; Jan 22, 2009 at 09:20 AM.