Thanks Scott, when did you try the A40's ? as I've heard the 2011 versions were drastically improved over the older 2010 series.
That would be this year mate, I just found they had an uninteresting sound, flat almost.
Your paying for a name associated with MLG(major league gaming), more than anything else.
A mixamp, or DSS(which I prefer, as it has bass boost and sound field wideners, as features), with a pair of Senns with no mic, or another set of cans with a mic, would not only save you cash, but sound better.
Sure they look nice, but in no way are they near the best.
I've had Sharkoon's X-tatic V3's which at the time I thought were ok, but they really aren't, IMO(and it's only IMO), as the positional still sounds like it comes from the sides, more than rear, and they don't have the best sound either.
Also tried an older set of X41's and they were ok, but the 2.4ghz had perpetual hiss.
The Sharkoon's also had a background noise, but in the shape of a "bleeping" noise, very annoying, and yeah, reports of mics failing, etc.
I went and got the mixamp, and Astros, and got rid of them within a few days, and did without for a while, till I tried the DSS, and picked up the PX21's at the same time, for around £100.
And that's what I've stuck with, the PX21's, DSS, sometimes, my in ear Senns from my ipod, a bargain from HMV not so long ago, which sound great, and a set of Sony MDR-XD200 that are around £15 or so, and sound a lot more expensive.
I've tried the Razor Chimaera's, (similar to the video, except they look more like the Razer Megalodon ), for a few rounds of BF3, using them at a friends house, and they are good, and work on PS3/Xbox 360, but I couldn't see myself buying them, they say 8 hours battery life, but his are lucky to get near that, and in his house, they again had an annoying background sound.
If you want to try out Dolby Headphone tech, just plug a pair of headphones, or earphones into your pc, or phone or whatever, and open Youtube, and search for the Dolby Headphone test vids.
That'll give you some idea of what to expect.
And the THX - Amazing Life trailer sounds immense too.