My revised system

Why are you pairing top-end parts with a budget PSU?
I would also suggest a better PSU, as you can get better ones for the money.

Also consider dual HD5850s, close performance for a lot less.
Finally, scratch the dual HDs, get a single Samsung F3 or WD FAEX, then a SSD.

An Athlon II x4 2.6GHz and a dual-chip 5970? Unless you are overclocking... you'll have some gaming problems...
Actually, nevermind that. I have no personal experience with the x4 and bottlenecking and the above is just a repeat of what others have said. Wait for someone else on that issue. In the meantime, check out this article:
http://www.tomshardware.com/reviews/build-balanced-plat...
http://www.tomshardware.com/reviews/balanced-gaming-pc,...
http://www.tomshardware.com/reviews/balanced-gaming-pc-...
http://www.tomshardware.com/reviews/balanced-gaming-pc-...

Especially the last article since it shows the hit of the less cache of the Athlon II and how it will impact your game.

I actually don't even recommend the 5970 because crossfire doesn't produce 1+1=2 performance. You will get a gain but not worth $700. And if you don't have the money to spend on a good CPU, don't spend that much on a graphics card.
The radeon 5870 is a good single card that I recommend.
That said, take it with a grain of salt because I am biased and stay away from multi-card/chip configurations.

Anyway, if you are getting the Athlon 2.6GHz because you intend to upgrade to Zambezi when AMD comes out with them, than good temporary choice but I would go with a cheaper, higher clocked, Athlon IIx3 for gaming as most games still cannot use more than 3 cores.

your blu-ray drive will play/burn to dvd/cd, so you don't really need the sony dvd drive

How about a AMD Phenom II X4 955 Black Edition instead?

That should serve you well.

Ok, the
AMD Phenom II X4 955 Black Edition it is...As far as crossfire, I only plan to get 1 5970.

The 5970 is basically 2 cards in one. It runs in crossfire with itself. Each of the two chips is above the performance of a 5850 chip and below a 5870 chip.
You will need to enable crossfire in order to get better than the performance of one chip.

Thanks..I didn't know that.

+1 Phenom II 955. I'd take nothing less from AMD to pair with the 5970.

Also, change that PSU, like has been mentioned. Get a higher quality brand in the 750w range.