Nvidia is pretty close in price/performance actually. A GTX 970 is cheaper than a 290X and very close in performance, not to mention its TDP is literally half that of the 290X.
The 970 is more than a 290 here, the 970 being £250-280 when the 290 is around £210-250! In America it's true but in the UK, no way. The 290x being around the same as a 970 and probably better performance, especially at higher resolutions such as 1440p.
GTX 970 starts at around £260, 290X starts at £280. You can get a 290 for £230 but it's not as powerful as a 970.
How is the 970 compared to the 290x? You can get a 290x for around £275 and a good 970 (MSI, GIGABYTE, EVGA, that sort) is around the same, if not more. So, what is the performance difference between the 290x and the 970? I CBA to research it because 1: I'm on my Nexus, 2: It's almost midnight and I'm tired as hell. I was considering a 290x when I was planning to get a Pentium in Novemberish and have always wondered what sort of performance I would get.
Only a bit better on the 290X. Overclocking the 970 should easily match it, and because it draws half as much power it's much easier to keep cool, allowing for higher overclocks.
I have had an i7 4690k before, but when I build this computer, I decided to go eith the 4690k and overclock it. Guess what, it is faster than the stock i7, there for, my 4,6 GHz clocked i5 is better than the i7 not including video rendering and plain old rendering. All in all, the i5 can achieve the same performance for much less, making it the better cpu. Now on the other hand, if you don't want to overclock and are willing to pay extra for that than go with the i7. Also, with the i7's hyperthreading, if you are recording videos than the hyper threading can help with that. (the same thing goes for streaming)