What are you using it for. 5 boxing ?

I would personally push the RAM a little more, to like 12 GB. Everything else looks overkill for WotLK 5 boxing. and I bet cata shouldn't be any problem either.

Also if WOW is the only thing, then you can degrade GPU , and get the best CPU you can get as WOW is CPU bound. But if you are into other games, this rig looks good.