It's $50 more to get the Asus motherboard and processor.
I suggested the MSI not only because it is cheaper with comparable features but also because it is AM3+, which means it is compatible with the next generation of AMD processors that is going to launch, eventually.
To add to the other reasons on pg1 about why I chose different parts:
4) Couldn't find the optical drive you selected, but generally one is as good as another.
5) The 6870 is much better than the 6770 (don't let the numbering scheme fool you).
6) The 650w PSU I suggested is enough to power the build, and a GPU upgrade up to a GTX 580.
7) That RAM is the best bang for your buck at that price.
Ok bought the 650w psu mentioned, got a 500gb western digital hd, went with the Asus mobo, got 8gb of crucial 1333mhz RAM, and got a steal on a Radeon 6770 with free Dirt 3. I also couldn't resist the Azza Hurrican 2000R case it just looks awesome