All of the advice above is sound, but I know sometimes you just want an answer within your parameters, so that's what I'm going to try to provide. All arguments of gimmickyness aside,
http
/www.razerzone.com/gaming-audio/razer-kraken-71-chroma may be worth looking at for your wants. Lots of audiophiles condemn Razer, but it seems like you're more interested in the 7.1 Virtual than perfect Audio, and with that in mind, you may like these. I have tried Steelseries Siberia V2 with USB soundcard, which were comfortable, but ear piece went out after like less than a year. If I was shopping for 7.1 virtual integrated gaming headset because that's what I wanted, I would probably give these a shot.
To put more simply what was said above, virtual 7.1 and perfect audio do not exist together. You sacrifice one for the other. I've used virtual 7.1 for gaming, and while the sound quality is not as good as it should be, it is more immersive for gaming. It may not sound great for music or movies, or maybe it will. it all depends on your expectations. You said you wanted a gaming headset with 7.1 for gaming, so that's what I'm suggesting. If you don't like them, you can always send them back and try something like
http
/www.amazon.com/Logitech-Wireless-Gaming-Headset-Surround/dp/B003VANOFY which are wireless and 7.1, but mic is questionable.
Finally, as far as the Tiamat goes, those are "Real" 7.1, which means there are 10 tiny drivers in the headset as opposed to 2 big ones. this means it might be the best surorund experience you can get from a headset, but the audio itself might be limited (for example, low bass) and they would probably sound really bad doing anything other than gaming with them.
In the end, nobody can tell you what you're going to like best because everybody has different expectations. We can suggest, but the choice is yours. Just remember you aren't locked into them for eternity. Trial and error. If you don't like them, send em back and try again. Hope this helps.
Bast