Building a new rig

it's kind of hard to build a good computer that can run the latest games on high with good fps with ~$800 to spend on the computer itself
i would take a look at these two threads

http://www.tomshardware.com/forum/380358-31-bestconfigs...
http://www.tomshardware.com/forum/380361-31-bestconfigs...

If you want to CrossFire later and overclock, here you go. Not sure if you need OS, keyboard/mouse.

PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU: Intel Core i5-3570K 3.4GHz Quad-Core Processor ($214.99 @ Amazon)
CPU Cooler: Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler ($29.99 @ Newegg)
Motherboard: ASRock Z77 Extreme4 ATX LGA1155 Motherboard ($129.99 @ Microcenter)
Memory: G.Skill Sniper 8GB (2 x 4GB) DDR3-1600 Memory ($43.98 @ Outlet PC)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($80.98 @ Newegg)
Video Card: PowerColor Radeon HD 7950 3GB Video Card ($274.99 @ Newegg)
Case: Rosewill Line ATX Mid Tower Case ($59.99 @ Newegg)
Power Supply: XFX 550W 80 PLUS Bronze Certified ATX12V / EPS12V Power Supply ($65.99 @ Amazon)
Optical Drive: Samsung SH-224BB DVD/CD Writer ($15.99 @ Newegg)
Monitor: Zalman MZ215ED 21.5" Monitor ($99.99 @ Newegg)
Total: $1001.88
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2013-02-08 10:41 EST-0500)

No I know what mouse I want, not sure about keyboards though. Would that rig play bf3, csgo, blackops 2, etc? I will spend as much as I need to. Thanks guys.

yes cball1311's build will be able to play all those games at the highest settings smoothly

Here you go.

Battlefield 3 - Ultra settings with 4xAA

http://www.techpowerup.com/reviews/AMD/HD_7950/8.html

and with new catalyst drivers as of 12.11

http://www.techpowerup.com/reviews/AMD/Catalyst_12.11_Performance/5.html

cool cool thanks guys  Now I just have to figure out how to build this thing.. anyone know of any good tutorials or something to help me out?

Best answer selected by toaztr.

one more thing, I dont need a case fan?

There are four optional fans that you can install on the case. So, here you go.

http://www.newegg.com/Product/Product.aspx?Item=N82E16835103052

the best building pc tutorial - http://www.youtube.com/watch?v=ea_bs5G1yYU

Thank you guys very much.