That would be a fine choice, but it's just the micro ATX version of the Extreme4 and it actually costs more money right now. Given that your case can support a full ATX board without issue, I'd stick with the regular Extreme4 and save $12.
I would get a cheaper case - that one is lovely, but the NZXT Gamma Classic is an amazing case for dirt cheap.
Also, I double up on the suggestions both for an SSD and a better graphics card. What resolution are you playing with? (And we're serious about the SSD. It'll do more to make the computer feel fast than anything else would.)
I wouldn't recommend it, it's usually best to do a clean Windows install when you have a completely new build like this. If you use my suggestion to spend the money you save from motherboard on an SSD instead, you'll definitely need a fresh install.