Good evening,
I have the k702, and wouldn't really recommend them for gaming, i am running them off my xonar STX (which admittedly isn't a great card for games), and my Canamp, but i find them a little lacking, for example, when a transition is made from left to right, IE: turning in front of a sound source, i find it very direct, without much smoothness straight from one ear to the other.
on the other hand, my HD595s seem to give off a better "3d" effect where the sound travels in front of you before reaching the other ear. this is just my opinion, but i always go for the 595s when gaming. the only downside is that the bass is not as impactful as the K7xx
i haven't tried any of the other AKGs for gaming, and the K5/6 might give of a better effect than the K7xx, but just thought i'd throw in my opinion
So if you are considering a different can, i would definately recommend the HD595 for gaming, they are also supremely comfortable, and will save you abit of money compared to the K7xx