Gaming computer 550$

PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU: Intel Pentium G850 2.9GHz Dual-Core Processor ($69.99 @ Newegg)
Motherboard: ASRock Z75 Pro3 ATX LGA1155 Motherboard ($79.56 @ Newegg)
Memory: Corsair XMS 8GB (1 x 8GB) DDR3-1600 Memory ($26.99 @ Newegg)
Storage: Western Digital Caviar Blue 500GB 3.5" 7200RPM Internal Hard Drive ($55.99 @ Amazon)
Video Card: MSI Radeon HD 7770 GHz Edition 1GB Video Card ($112.99 @ Microcenter)
Case: MSI TC- (Black) ATX Mid Tower Case ($24.99 @ Microcenter)
Power Supply: Corsair Builder 430W 80 PLUS Certified ATX12V Power Supply ($24.99 @ Newegg)
Optical Drive: Asus DRW-24B1ST/BLK/B/AS DVD/CD Writer ($16.99 @ Newegg)
Operating System: Microsoft Windows 7 Home Premium SP1 (64-bit) ($91.99 @ Amazon)
Total: $504.48
(Prices include shipping, taxes, and discounts when available.)

This build is quite good, however before rebates it costs $564.91, after rebates is $504.48; I really like the case, power supply, and video card. For the price the Intel Pentium G850 is best in class, although you could upgrade to the Pentium G860 which gives 100Mhz for $5 more.

Here's ready solution http://www.tomshardware.com/reviews/gaming-pc-overclock... just scroll down a bit
Though OS not included

I would get an amd A10. It's super cheap and can run all games pretty well. You won't have to buy a separate graphics card. You can build a system for about $500.

^ Also true.

Here's how it looks.
PCPartPicker part list / Price breakdown by merchant / Benchmarks

CPU: AMD A10-5800K 3.8GHz Quad-Core Processor ($124.99 @ NCIX US)
Motherboard: ASRock FM2A75M-DGS Micro ATX FM2 Motherboard ($55.98 @ Newegg)
Memory: G.Skill Sniper Series 8GB (2 x 4GB) DDR3-2133 Memory ($34.99 @ Newegg)
Case: Corsair 300R ATX Mid Tower Case ($64.99 @ Newegg)
Power Supply: PC Power & Cooling Silencer MK III 500W 80 PLUS Bronze Certified ATX12V Power Supply ($71.74 @ Amazon)
Optical Drive: LG GH24NS90 DVD/CD Writer ($22.98 @ Newegg)
Operating System: Microsoft Windows 7 Home Premium SP1 (64-bit) ($91.99 @ Amazon)
Total: $467.66
(Prices include shipping, taxes, and discounts when available.)
(Generated by PCPartPicker 2012-11-12 13:44 EST-0500)

Here's example benchmarks for a10 5800K and other trinity based apus http://www.tomshardware.com/reviews/a10-5800k-a8-5600k-...

wow, thats alot of rebates. i think i might just throw a extra 50 into the gpu and cpu, ill go with the 2nd cpu you suggested, but what should i do for the gpu.

I'm not quite sure, I'm not very educated on all of the current nvidia and amd video card line up, however I would look at this: http://www.tomshardware.com/reviews/gaming-graphics-car... and this http://www.tomshardware.com/reviews/gaming-graphics-car... .

This is the way to go, although you can now get a HD7850 for the same price (a Powercolor model, which should be fine). Of course, that price was without the OS...
Do not get the 430W V2 Corsair "Builder." It was made by CWT (not Seasonic), using inferior Samxon capacitors from a line known to fail. Links available on request, but it begins at HardwareSecrets, a site I trust for PSU information.

^ Why are they allowed to rebrand -____-

removed

^The only thing I'd change in that list is the Apevia case. I owned one...one only. It was junk; a nice design, but poorly executed, and with the flimsiest possible materials. As to quality control, a factory drone put a screw through the power switch wires, shorting them. After a few months of contending with static-induced reboots if my fluffy cat even walked near it, it ultimately ended up in the garbage.

will this work?

memory- CORSAIR Vengeance 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Low Profile Desktop Memory Model CML8GX3M2A1600C9
40$

os- Microsoft Windows 7 Home Premium SP1 64-bit - OEM
99.99$

case- NZXT GAMMA Classic Series GAMA-001BK Black Steel ATX Mid Tower Computer Case
34.99$

storage- Western Digital WD Blue WD5000AAKX 500GB 7200 RPM SATA 6.0Gb/s 3.5" Internal Hard Drive -Bare Drive
69.99$

gpu- PowerColor AX7850 2GBD5-DH Radeon HD 7850 2GB 256-bit GDDR5 PCI Express 3.0 x16 HDCP Ready CrossFireX Support Video Card
184$ 10$ rebate

psu- Antec VP-450 450W ATX 12V v2.3 Power Supply
40$

mobo- ASRock H61M-DGS LGA 1155 Intel H61 Micro ATX Intel Motherboard
44.99$

cpu- Intel Pentium G860 Sandy Bridge 3.0GHz LGA 1155 65W Dual-Core Desktop Processor Intel HD Graphics BX80623G860
74.99$

total 589.92, 569.92 after rebates.

That works, although I think the B75 mobo would be a much better choice. Going too cheap anywhere is really asking for some kind of trouble.