Headsets that claim 7.1 stereo really just emulate it. If you want, you can do the same thing with your motherboard's sound card. If you have the driver's installed, there should be an option in the driver's control panel to turn on "DTS" or "Dolby Virtual Surround". 7.1 is really just a marketing gimmick as most people can already emulate it if needed.
"now I do have to admit I will be using them more for gaming rather music."
On a whole, the ATH-M50s will handle both good but it does have some specific weaknesses. They aren't the best at classical (although certainly better than any gaming headset by far) and they can be a bit uncomfortable after a very long gaming session (Talking 3+ hours). You can buy earpads that fix this although it ins't a huge issue, more like a minor flaw.
I don't know if I mentioned this but there are many fakes of these headphones due to their value to sound ratio. Make sure that you buy from reputable source. If you have any doubts about the cans you receive, you can tell them apart by comparing them to real ones. There are actually many articles around with high res pictures just for that purpose so all you need to do is google "ATH-M50 Fakes".