What's a good gaming PC for under $800
All I'm really going to do on it is gaming so don't worry about editing and rendering
!NOTE!-This has to include OS and Monitor
I might have a few suggestions. But first, how important is it for you to have the best graphics running at the smoothest framerates? Also, how long would this computer need to last you? I tend to upgrade my computers in parts. Every 2-3 years I upgrade the GPU while the CPU/Mobo/RAM is done every 3-5 years. I would recommend an AMD build since you stated this will be a gaming rig.
Tek Syndicate also did a really good video on building a $550 gaming rig. If you add an OS and monitor to the mix you should be right around $800.
https://teksyndicate.com/videos/build-best-budget-gaming-pc-february-2013
I can also personally vouch for the AMD 955 processor. I used it in my last build and it performed very well.
I'd start with this. http://pcpartpicker.com/user/tacticallemur/saved/2n41
It's over budget but you can start with this and work down to your budget but I would save up a tad more money and get something similar to this. You can get AMD quad cores for cheap and step down in motherboard but I'd still go with this CPU motherboard for the money. If you live near a microcenter you can save like 30 bucks buying them as a combo. I swear they aren't paying me to say this even though I say it on every build lol. You can sac the cooler for a little savings and if don't want to overclock. I'd get one later though because overclocking is fun. Can sac the CD drive if you don't need or want one. This will get you 1080p gaming at pretty much max settings.
http://pcpartpicker.com/p/1CQDV
This fits your budget.... barely lol. But its all quality parts.
AMD 6 core processor, AMD 7950, Corsair power supply, it's also got cas 8 1600mh ram.
The lowest quality part of this build is the case, which is still a good case.
This is what I would buy with my money on this budget. If you can get a little more, then I would consider getting an SSD as a windows drive. Really speeds things up.
That's a good build from feralshad0w. Keep in mind, this setup can run BF4 at high! The recommended are 6 core AMD and 7870. You have 7950 (which is better), so you can play BF4 at high!