Thinking I5 750 atm.
ALSO
Single Sapphire ATI Radeon HD5850 or Cross fired?
EDIT*
I will be using the system to run games such as gta 4 and such in high detail.
He is a rough idea of the system i have atm.
Intel Core i5 750 2.66Ghz Quad Core Processor 8MB LGA1156
APACER 2GB DDR3-1333MHz CL9 Lifetime Warranty X3
GIGABYTE P55-UD Intel P55 Chipset Socket 1156
Seagate 1TB Barracuda 32MB 7200.12 SATA
BenQ 22x Speed internal DVDRW SATA
Sapphire ATI Radeon HD5850 1GB GDD5 PCI-E Video card X2 Or not?
THERMALTAKE Element G GAMING CASE
Gigabyte ODIN PRO 800W PSU 140mm FAN