Oh, and in your original build you forgot a DVD drive. My build includes one.
If you are dead set on an i7, I would be pretty confused considering your main purpose is gaming. If your set on intel an i5 is a better bet. But going AMD is your best best for gaming right now, and the AM3 platform is not going to die off anytime soon.
The mother board I picked has a dual x8 mode for crossfire and an x16 for a single GPU system. A second 5830 later on will get full performance from that motherboard. The one you chose has a single card at x16, but if you add a second card it only gets x4.
x16 / x4 is a lower performance crossfire board than x8 / x8.
Your HDD is a good choice.
Getting off the i7 platform frees you from triple channel RAM setups, and the one I chose are super fast and priced very well.
The PSU you chose is not solid. The one I chose is Crossfire certified, modular design and 80+ certified, with ample 12v rail amps and is 700w also.
Newegg has EGGCELENT deals if you hunt for combos, which I have done for you. Let us know what you decide!