As everyone already said : SSD !
about the cpu : i5 is more than fine for gaming, i7 is pointless.
About the gpu : what is your screen?? (definition, refresh rate etc...) because if you have something like a 1080p 60Hz it's pointless to buy a 980...
You should check out Ed's video about the mouse he uses for CS GO (he's global), I think it's the final mouse or something like that (there was also a new version of the mouse and he reviewed it too).