Wow guys, well covered.
Andrew, first build has a good i5 quad core processor and a beasty 770 graphics card, that will net ultra settings on most games and high on everything else
Second build offers a unlocked and overclockable i5 quad core. Its a little faster and can be made to go even faster, and offers a better motherboard. But at the cost you get a 760 graphics card, step down from the 770. Should play high everything, ultra on some maybe.
Third build, amd build, offers 8 cores but aren't as strong as intel cores. So for gaming its gives you the beasty 770 graphics card, but processor isn't as strong as the intels. But it offers 8 cores vs 4 cores, so for multi threaded things such as video rendering, 3d graphics, and intensive programs, it should offer a lead over the intels
But either amd or intel, you really cant go wrong, AMD is great budget cpu, and isn't as fast as intel but is really close.
So first build if you don't plan to overclock and want good graphics card
Second build if you want to overclock and play around with your chip to make it go faster, better quality motherboard, but step down in graphics
third build if you want to overclock or not, better quality motherboard, and great graphics card.