Best Mobo for this build

Ok, so, I am looking to build an AMD Phenom II 955 based computer, but cannot decide between an asus 790gx or 790x. I am going to be purchasing a Radeon 5770 most likely, so not sure if the onboard video for the GX will be a plus at all, or just sit there. Here are the links to the two boards...

Asus 790GX
http://www.newegg.com/Product/Product.aspx?Item=

Asus 790X
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

With a combo deal, I can get Either the GX for $30 less, or the X for $60 less. Hope that helps a little!

A little other information on what I plan to run...

AMD 955
8 GB DDR 3 Ripjaws Lat 7-8-7
WD Caviar Black HD
Sapphire Radeon 5770, eventually hooked up to a LCD/HDTV
Corsair 750 watt PSU

Please let me know what you think, and why one would be better than the other. Thanks again for your time!

- C