I've been doing some research and this seems to be the cost effective way to get a gaming computer i have around $450-$650 and would like to play games like dark souls/borderlands 2 on average setting if i can get the parts a local store that would be better any help would be appreciated
You have a fair bit of cash left, around $100. Where you want to put the cash is up to you. Good options I can see is a better case, an SSD, a CPU/mobo upgrade or a better GPU.
If your after longevity over a long time frame, then I advise the case upgrade, as that will last longer than any of the stuff inside it.
If your after longevity over a medium timeframe, then I advise the CPU mobo upgrade. Get a 3570k and a Z77 board. That means the rig is easily upgradable (can just throw any new GPU you want in without fear of bottlenecking).
If your after performance right now, upgrade the GPU to a 7850/660.
If your after blazing boot up times and general responsiveness in the rig, then get an SSD.
Yep, thats whats good about custom machines, its relatively easy to replace components in the rig.
Though of course make sure that your machine can handle any upgrades you think of beforehand. For instance, throwing in another graphics card for Crossfire/SLI isnt possible on this rig, the PSU is too small and the mobo doesn't support dual Crossfire/SLI adequately.
I wouldn't throw $120 away on a dual core processor and turn around next year and buy a decent quad core. why not add $60 and buy it now instead of spending another $180 next year ? dual cores are next to useless.