I rebuilt my old gaming pc into a new case for my wife after I upgraded. This thing will still tear through 1080p gaming at high frame rates and reasonable graphical settings. Using the stock cpu cooler and keeping all the clocks at stock so the 750w power supply isn't really taxed. The 500 series gpus can start to really get power hungry when you overlock them though.
If I were to do anything more to this build I would probably add an aftermarket air cooler and a bigger power supply, then crank the clocks up as high as they'd go and run it 'til the wheels fall off.