If you are doing strictly gaming and web browsing/watching YouTube, doing school/college assignments and stuff (like 95% of people) then having a Intel Core i7 will literally offer no benefit to you (other than you probably feeling good you have TEH i7 SO GOOD MUCH SPEED AND POWER). In reality, unless you are doing something compute intensive like rendering content, photo manipulation, heavy streaming etc. which not many people do then an Intel i5 for now will be every bit as good as an Intel i7.
I suppose you can argue that an Intel i7 is future proof because games don't utilize hyper threads (which is the only difference between mainstream i5s/i7s) and when they do an i5 will be obsolete, but that's apparently been questioned for years and you still don't need an Intel i7.
Sorry for going on a rant. In terms of GPU performance, a 290X and 970 are similar performance, difference being the 970 is quieter and consumes less electricity (the latter being hardly anything to worry about). So whichever one is cheaper I would go with.
If you intend to over clock, that PSU won't cut it. I would go for Corsair HX/AX/TX or Seasonic, EVGA..*mind blank* but Corsair Builder will not be sufficient for overclocking. Hope that helps.