the z300 looks amazing!

I'm still sticking to my unbranded headset, but I believe 7.1 is necessary for gaming. I had my eyes on G35/Vengeance 1500 for a while but then dropped it due to its costiness. Although if I ever build a PC by the end of this summer I might throw a headset in there.

Oh, and I believe sound cards do not get affected by temperature that much, plus you have your GPU's cooling which should be more than enough for the sound card, unless you have everything watercooled.