Help build PC.......again.

[Darkslave]

Well, what do you want to optimize really?
Your mobo has 3 pci-e 16x slots, so you could always chuck another 460 in there, 750 watts gives you plenty of room to do that.
Other than that, cpu upgrade will be expensive. You'll either have to get a very high spec socket 1366 i7 which will quickly run you over $500 for the 970 and up, or buy a new mobo along with it.
Edit: or is this a build you're planning to buy? It's not entirely clear, by the age of the processor I'm guessing you already own this.