Too many questions @_@
Let's say I wouldn't want to go over 100€.
Yes I will use it mostly for gaming and I don't usually listen music through my headset. I have no clue what circumaural or supra-aural means D:
Well the best experience for gaming comes from a circumaural headset which means it fits over and covers completely your entire ear. They usually have 5 - 7 speakers in each head phone side for 5.1 or 7.1 surround. So when you are playing and something gets behind you, you actually hear it behind you not from the side or in front.
For 100 euros, you can get the Corsair Vengeance 1500. They ARE virtual 7.1 which means that they try to imitate the sound of someone behind you. They are cheaper than the tiamats and are made of metal! It cost less too! Tiamat seems to cost 179.99 Euros and it cost $179.99 on amazon so I find it funny that you pay less if you buy in the US