indeed, but is double channel a bottleneck for me, cause the Motherboard is a sucky one, but with the intel version I could have tripple channel (x58)
If your primary usage is gaming, 4 GB is more than enough, no matter how sucky the board is. The memory won't be a bottleneck, in any case.
Also the games you mention do not require very high end systems. Here, even the 5870 is overkill, unless you're on 2560 X 1650 resolution or something (though even that would be very playable on mainstream cards).
So I'd say, go the AMD way.
No doubt, the Intel rig is much more powerful, so if you don't mind spending the extra cash, get that. But still, I'd save on that & get a good SSD.