CPU: Intel i5-2400 ($184)
Motherboard: Asus P8P67-M PRO ($141.95
RAM: G.Skill F3-12800CL9D-4GBNQ (2x2GB) DDR3 ($45)
GPU: MSI R6850 Storm II 1G ($156.54)
Case: Antec 300 ($59)
PSU: OCZ ModXStream Pro 600W Modular ($89)
Total Price: $675 +$19 Postage of RAM + PSU from PC Case Gear.
You can save $75 by downgrading from an i5-2400 to an i3-2100, and you can save another $42 by downgrading your motherboard to a Gigabyte GA-HA65M-UD3H-B3 (note you'll sacrifice a lot of features including Crossfire capability, but you'll still have everything you need including SATA3 and USB 3 support.)
Bit too pricey :/
Originally Posted by Doc
If all he does is play CoD than 4GB is more than enough for it. I have 2GB and I'm playing it maxed out.