5.1 and 7.1 aren't 'gimmicks'. It's more they offer really crap value for money due to either it using Dolby Headphone with a poor DAC chip in the amp it's attached to when say a Asus soundcard with Dolby Headphone is better and the headset is of poor quality. With 'true' 5.1 / 7.1, the amount of drivers [the audio mechanical part, not the software definition] needed for the headphones results in designing around poor quality drivers, resulting in very poor sound quality for the money. Also due to costs, they often skimp on build quality of the headphone frame and/or comfort due to it. Not to mention increasing with games, they often come with their own software-based surround sound programming based around stereo output.
Anyway, this craps all over the other suggestions:
$299 free ship new
There's a few refurb'ed ones from beyerdynamic themselves in custom colours!:
Camo version!: $271 shipped
Another (IMO much better looking) Camo version: $271 shipped
Honestly, just based on sound, they laugh at the other crap POS suggestions. However a stereo headphone and separate mic of choice is much better value for money. That said, for a boom mic AND they awesome camo, I'd make an exception and feel that its worth it. It's from beyerdynamic USA themselves as well, so you know it's been refurbed to top specs. There are other shipping choices if you want faster ship.
Budget for soundcard?
Also, G35, G930 and A40 are total crap. Quality of advice > quantity of advice. Would you rather buy a headphone from a company that actually specialised in headphones and audio equipment, or a 'gaming brand' and mice maker?