Here’s a variant at $1133 after rebates: http://pcpartpicker.com/user/ShikataGaNai/saved/b8Mrxr
At that price I think that what you already have is about the most balanced build you can get. The 970 is a great card, unless you’re willing to spend another $200 for the 980 you can’t upgrade from it. Same thing with the 4790, excellent CPU, and the next step up is going to be a big premium.
The only thing I would add (if you’re willing to go a little over budget) is an SSD.