You can disable onboard sound and video on most motherboards that have either, and then put in add-on video and sound cards.
The motherboard you've listed is a decent board, (though it has onboard sound and ethernet, not too unusual today). I prefer motherboards by Asus, but that's personal preference, there are probably people here that would prefer MSI, as they are a good brand. One point: I'm not a fan of VIA chipsets, after having some AGP 4X issues with one of their older chipsets. However that's a personal bias, you should ask around here what other AMD users would pick for a good motherboard/chipset, you'll probably get some good advice.
That case is 20.9 inches high x 8.1 inches wide by 20.5 inches deep. Use a ruler to imagine it's size. It's a nice sized case, and it is pretty easy to cool that particular tower. (I was looking at those, in fact, around 6 months ago, still haven't decided what my next case will be though).
It think that about covers it. :)