Couple of things,
You don't need to do push/pull on an H100i if you have those Corsair SP fans, and do not use SP fans for unrestricted air flow.. they won't be any good. Go with the corsair AF series for unrestricted air flow.
As people have said, go with a newer card. I'd suggest a GTX 780. R9 290 is decent, but too expensive now IMO.
I say you keep the 750W PSU. It really isn't that much of a jump in price from something like a 550W to a 750W. Then you won't have to worry if you add a bunch more components.
Everything else looks good. You're going to love the K70 and M65.