build a i7 quad core system

Actually.... I built one already!

XMS3 6GB DDR3-1600 (PC-12800) CL8 Memory Kit (Three 2GB Memory Modules)

GA-X58A-UD3R LGA 1366 X58 ATX Motherboard

Radeon HD 5770 1GB GDDR5 PCIe 2.0 Graphics Card

Nine Hundred Two Mid Tower Gaming Case

CU-700B 700 Watt ATX EPS/12V Modular Power Supply

WESTERN DIGITAL WD10EARS Caviar Green 1TB 64MB cache SATA 3.0Gb/s 3.5
2 Hanspree 20" HF207 monitor

Came up to be around 1300.