1- I would change the mobo for the GIGABYTE GA-790FXTA-UD5 is a very good mobo less expensive that the Crosshair III
2- THIS have the similar performance that the spinpoint f3 500GB (currently unavailable)
3- With the same price of your PSU you can get THIS ONE that is a better PSU, or save a little money and get THIS, both PSUs are enough for your rig.
My suggested PSU and case together is $154 after MIR. My selected PSU and case is only $25 more and the PSU is of much higher quality and will allow CF 5870's in the future.
The processor that you selected is great, however 4 processors aren't used at all in gaming. Madadmiral had said in a post around here how the 4th processor can actually slow down gaming performance to where as 3 processors are perfect.