Need Help Building Budget Gaming PC

Hi, i'm in need of help with building a budget gaming PC
I'm looking to build a PC that's around $500-600, something that can enter me into gaming PC's.
I don't know much but I will give preferences and such.

I will mainly be gaming on the PC more than anything else.

I want to have a good video card that can play titles such as :

Shogun 2: Total War
Modern Warfare 2
Battlefield Bad Company 2
The Sims 3

and similar select titles on High to Ultra settings.

I would appreciate a NewEgg list of hardware to buy for the computer.
I don't know little to anything about building.
I do know a person that can build the computer for me and is an expert at doing so. I only need the parts that are good with my preferences.

I am in the USA which is IMPORTANT.

I want Great performance and Good Quality.  


It can have overclocking aswell.