I'm using 7 with no desire to change. I have 8 on my laptop, and it's cool, but I just prefer 7 on my gaming rig, everything that I ever need access to its right where I can find it, and it runs flawlessly.
I have read about win 8 being more cpu hungry, causing some gamers issues in newer games like bf4, but since I have no first hand experience with that, you'll have to let your fingers do the walking.