for $500
Athlon X4 750k-$85
http://www.newegg.com/Product/Product.aspx?Item=N82E16819113328 (I wasn't really aware of this CPU, but it seems
quite nice for the price and is quad core) (heck even better:
"A small observation: 750K X4 is 3.4Ghz/4Ghz stock/turbo 2M part with unlocked multiplier. It OCs to ~4.5-4.6Ghz on air cooling and keeping it at stock is a shame ." )
cheapo motherb-$50
http://www.newegg.com/Product/Product.aspx?Item=N82E16813130661
8gb ram-$60
http://www.newegg.com/Product/Product.aspx?Item=N82E16820313080
Decent PSU-$20 after rebate
http://www.newegg.com/Product/Product.aspx?Item=N82E16817171046
Cheap case-$20
http://www.newegg.com/Product/Product.aspx?Item=N82E16811192289
hard drive-$60
http://www.newegg.com/Product/Product.aspx?Item=N82E16822136769
Windows 8 OEM license (or Win 7 if you prefer, same price) $100
http://www.newegg.com/Product/Product.aspx?Item=N82E16832416550
That leaves you $105 for your GPU
HD 7770 1GB, $95 after rebate
http://www.newegg.com/Product/Product.aspx?Item=N82E16814131477 Which also comes with Far Cry 3 and Far Cry 3 Blood Dragon to boot. Which technically you could probably throw on ebay for a few bucks too.
You have $10 left over for shipping (although you are counting on two rebates)
I must say, I consider the above build a masterpiece. $500 and
including windows. The PSU is even very good quality 460 watts cooler master. Fear my newegg-fu.
It's very similar in specs to the consoles, of course. 8GB RAM and a 1.2 TF GPU.
It does show you are getting a pretty good deal with the consoles. This is specced similar to XB1 but doesn't include Kinect, and is $100 more and with less powerful GPU than a PS4.
Edit: Just realized forgot to include a DVD drive. Like floppy drives of old not sure how much longer it's needed, but you can get one for
$15. That would put you $5 over budget, plus a few bucks for shipping, or you might be able to squeeze a few bucks out elsewhere, sell those games on ebay or something, if you want to be really strict on $500.