Double check the EVGA x58 board to make sure it can handle Crossfire... most x58 boards can but EVGA has always support Nvidia GPU's only, so I'm not sure they support ATI.
This close to ATI's release of their DX11 (5870), I would not recommend getting two 4890's. You would be better suited buying one now and adding a second when prices drop or save more up and upgrade to the new 5870, which is believed to be better than the 4870x2 with only one GPU.
You don't need 12GB of memory unless you are doing high level Photo editing for CAD work. If this is a gamer build... stick with 6GB of OCZ Platinum 1600.
I would not recommend getting the Cooler Master V8. You would be better suited getting either the Xigmatek Dark Knight S1283V or COGAGE TRUE Spirit for better performance at a cheaper price.