I'm not sure about the power requirements for the 970 and 4790K but a 500 watt power supply doesn't seem like enough to me. I would suggest 700 watt, but perhaps I am wrong. I personally have a 4770K with a 290X and know it can run on a 750watt power supply. I do know that the 970 is MUCH more power efficient but don't know if 500 watt is enough.
Awesome specs though, that will go beast mode on any 1080P games ;)