Which combination would be better? A FX-6300 & a AMD HD7950 or 3570k & AMD7870.
I'm leaning towards the FX6300 because it's slightly cheaper but the only issue is that perhaps the cpu will bottleneck the gpu in the future?
I don't think that CPU will bottleneck a future GPU, seeing as next gen consoles are going 8-core, FX will only get better. Although the 3570k will provide a better experience now, if that's what you are shooting for, albeit with a slower GPU.
A 3570k is what I'm saving my money for though. It is going to be paired with a gigabyte 7870. I'm using the 7870 with a Phenom II right now, and it doesn't bottleneck. I'm pretty confident the 6300 won't bottle the 7950.