If I never had to buy extra components, I would have went for almost that exact same setup.
The 580 is a monster in terms of performance, and the i5 2500K is the preferred gaming CPU of choice. I went for the i7, no idea why.. Just having extra threads appealed to me.
Maybe future me wanted a faster CPU to anticipate a new GPU buy?
Damn future me! He doesn't know how to manage money!