I'd replace the CPU/mobo with i5 4670k and a Z87. Slightly better performance and lower power consumption for around the same price.
Also, two 670s for that price...not a great deal. Agree that two 4GB 770s would most likely last longer into the future, and are not that much more. I would not go with Crossfire until they get the stuttering issues worked out, if you'd rather get 2 Radeon cards.