Nothing is future proof.
That is a nicely balanced reasonable system.
You will have options.
If you need a cpu upgrade, you can replace the duo with a quad.
If you replace the GTX660, you have today, a GTX680 as an option. Possibly more with a GTX7xx.
If you own the case, keep it and see how you do.
Your parts do not generate lots of heat and you can always add a fan later. I suspect you will not need to.
If you want the best M-ATX case out there, I can personally recommend the Silverstone TJ-08E.