My first build, $550

For gaming i really recommend going for a cheap AMD quad core cpu and a discrete graphics card.
This video really shows the difference in price/performance between cpu + gpu against apu
https://www.youtube.com/watch?v=lpGfA6g0-0Y


I've made this list with a cpu + gpu for around $600
http://pcpartpicker.com/p/3ixx2
Their test clearly shows this cpu + gpu as a price/performance winner and there is exactly space in your budget for it!

the apu would do low/medium in 1080p and the 750ti will do medium/high in 1080p!

Hope this helps

http://pcpartpicker.com/parts/partlist/

Something like this would be a better bet, also perform better. Also 2400Mhz ram is not necessary by any means and that mobo won't run that speed.

Just changed some stuff on your the list in the other post, so it actually comes around $550! And it is cheaper and better. (x2 HDD space, asus PRO motherboard)
http://pcpartpicker.com/p/3ixx2
i really recommend this build!

For the record, that build with the A10-7850k would be a lot better than everybody thinks, but I think you can do better in that price range.

Here are three builds

This is the best under $550

PCPartPicker part list: http://pcpartpicker.com/p/3iK90
CPU: Intel Core i3-4130 3.4GHz Dual-Core Processor ($118.93 @ OutletPC)
Motherboard: MSI B85M-P33 Micro ATX LGA1150 Motherboard ($58.98 @ SuperBiiz)
Memory: G.Skill Ripjaws Series 8GB (2 x 4GB) DDR3-1600 Memory ($67.50 @ Newegg)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($54.99 @ NCIX US)
Video Card: EVGA GeForce GTX 750 Ti 2GB Video Card ($149.99 @ NCIX US)
Case: Cougar Solution (Black) ATX Mid Tower Case ($39.99 @ Newegg)
Power Supply: SeaSonic 300W 80+ Bronze Certified ATX Power Supply ($39.99 @ Mwave)
Optical Drive: Samsung SH-224DB/BEBE DVD/CD Writer ($15.98 @ OutletPC)
Total: $546.35



You could fit an i5 for under $620

PCPartPicker part list: http://pcpartpicker.com/p/3iKan
CPU: Intel Core i5-4570 3.2GHz Quad-Core Processor ($189.98 @ SuperBiiz)
Motherboard: MSI B85M-P33 Micro ATX LGA1150 Motherboard ($58.98 @ SuperBiiz)
Memory: G.Skill Ripjaws Series 8GB (2 x 4GB) DDR3-1600 Memory ($67.50 @ Newegg)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($54.99 @ NCIX US)
Video Card: EVGA GeForce GTX 750 Ti 2GB Video Card ($149.99 @ NCIX US)
Case: Cougar Solution (Black) ATX Mid Tower Case ($39.99 @ Newegg)
Power Supply: SeaSonic 300W 80+ Bronze Certified ATX Power Supply ($39.99 @ Mwave)
Optical Drive: Samsung SH-224DB/BEBE DVD/CD Writer ($15.98 @ OutletPC)
Total: $617.40



Or you could stick with the i3 and get a much better video card

PCPartPicker part list: http://pcpartpicker.com/p/3iKkO
CPU: Intel Core i3-4130 3.4GHz Dual-Core Processor ($118.93 @ OutletPC)
Motherboard: MSI B85M-P33 Micro ATX LGA1150 Motherboard ($58.98 @ SuperBiiz)
Memory: G.Skill Ripjaws Series 8GB (2 x 4GB) DDR3-1600 Memory ($67.50 @ Newegg)
Storage: Seagate Barracuda 1TB 3.5" 7200RPM Internal Hard Drive ($54.99 @ NCIX US)
Video Card: Sapphire Radeon R9 270X 2GB Video Card ($215.99 @ SuperBiiz)
Case: Cougar Solution (Black) ATX Mid Tower Case ($39.99 @ Newegg)
Power Supply: EVGA 500W 80+ Bronze Certified ATX Power Supply ($39.99 @ NCIX US)
Optical Drive: Samsung SH-224DB/BEBE DVD/CD Writer ($15.98 @ OutletPC)
Total: $612.35

It depends on what you want to upgrade first down the road. The i3 + 270x would be better for gaming right now, but you would want to upgrade that i3 in a year or two. The i5 + 750ti is a much faster PC overall in everything but gaming, but you would want to upgrade that 750ti in a year or two.

So you could just pay the extra money now and get the i5 + 270x hahaha