To be honest, if you want to make a comparison like this, you should try to keep both rigs at the same price, so that it is easier to compare. We don't know whether or not you actually care for the extra $300 difference.
If you are going for gaming only, definitely AMD. Not much of a performance gain if you go intel on this one, as games don't even need 8 threads. :/
With the extra $300, you could actually settle for 2 x 5850. That would make the AMD build more worthwhile in terms of gaming FOR SURE.
Heck, you can even keep the AMD build at that, but get a 80GB Inten X25-m SSD for your Windows just for the lols. >.>