Power supply is one spot, the 500w Antec basiq, 500w OCZ StealthStream and the Antec Earthwatts 500w would save L10-L15 and are quality power supplies. Since you didn't mention crossfire the MSI AM3 770 or Asus AM3 785G or Asrock AM3 785G would save some cash.
The 500GB WD drives are older 250GB platters, the samsung F3 uses a single 500GB platter, it will cost you a bit more and ebuyer's doesnt seem to stock it but it would be faster, its actually the fastest conventional drive available http://overclockers.co.uk/showproduct.php?prodid=HD-081...
I have changed the power supply and the hard drive to the ones you both reccomended.
The reason i chose this motherboard is that it has the SB750 chipset, which i read increases the overclocking capabilities with this CPU. But i may change it as it is £20 cheaper.
Aside from that, is the build compatible and do you see any other problems?