In terms of gaming performance, when you go from mid range machine to high end machine, you are often spending 2-4 times as much without 2-4 times the performance. You hit diminishing returns big time.

I go with generally mid range components with my gaming machine. Even then, I upgrade every 3 generations for CPU and every other generation for video card. CPU performance doesn't impact gaming as much as it used to.

This gives me reasonable performance in most games around high to ultra on a 1920x1080 monitor.