Hey bro listen. Building a PC is really easy. What you should do is find someone who knows how to do it, pick out your components and yeah! It'll be cheaper, and probably faster than the one you have picked out.
(By the way, don't go with an AMD processor when you have $640 to spend!)
I'm only interested in a pre built pc anything that needs assembling is not my cup of tea. Maybe down the road i might build one, i've always wanted to build a pc from scratch but now is not the time. So any suggestions of any good pre built pc's would be great, also i would like to add that i play on 1280x1024 resolution on all of my games, no interest in playing anything higher than that, basically high to ultra settings on said resolution would be fine with me.