The eight cores of this new gen are basically for all the multimedia multi tasking while you game right?
When it was released, people said the i5-2500k was the perfect gaming CPU, which is what I am running.
I think my CPU can probably last until the end of this PS4, XBONE generation, all I really have to do is upgrade my GPU graphics card.
No, the multiple cores allow for more power because at the moment it's very hard to increase a core speed, but you can increase a processor's speed by adding more cores of the same speed. It does mean multi-tasking works better, but it's mainly the easier way of increasing speed without having to actually increase the clock speed.