I'd recommend that you build a Sandybridge rig instead of an X58. Try this one at scan: http://3xs.scan.co.uk/ConfigureSystem.asp?SystemID=1015
Okay, so here is what I'd be looking at:
CPU - Intel 2nd Generation "Sandy Bridge": Intel Core i5 2500K 3.3Ghz Quad Core overclocked to 4.7Ghz
8GB Corsair Vengeance DDR3 1600 Mhz
2 x 6950 Crossfire
850 Watt PSU
As well as other stuff like the storage drive.