It depends on the GPU,i5 and i7 perform similerly in games,for anything else than gaming such as recording,editing,i7 is prefered,if mainly for games,i5.
Minecraft is definitely cpu intensive and intel has stronger cpu cores. You'd be better off with an i5 for best performance/value out of the three. Or an i7 if you don't mind spending a bit extra and need the hyperthreading.
minecraft is more of cpu intensive than anything and benefits from strong cores, the i5 would be your best option and video card doesnt really matter my gt 630 when i had it got me 200 fps offline but my cpu usage always would go up on servers dipping my frame rate