Why not a Corsair HX series power supply? I have one and it works great. Akasa are not known here fore quality power supplies. Thousgh I do have the Akasa Nero CPU from them (its silent).
I agree with the above ditch the Rampage, I have an Asus P6T which can do SLI and Crossfire (I think it costs 150 pounds now).
Why not go for an OEM version of Windows 7 64 bit? That would save you a few pounds and well, why waste it on the full retail version when the OEM works fine. In case you are worried, if te motherboard does break (classed as the computer in a PC) then all you have to do is phone Microsoft, they are usually very helpful.