I'll just say that CMSS-3D Headphone is the one thing that made me forget about surround speaker systems altogether, and also the thing that got me into Head-Fi. Now I'm packing a Stax SR-Lambda as my headphone of choice...excellent, but expensive. (And it's still way more affordable than the flagship SR-009...)
I am pissed at the state of gaming audio these days, though. Microsoft had no reason to remove DirectSound3D from the Vista sound stack, or even to remove the control panel for setting the default MIDI device, among other things. But no, now we have this software-mixed XAudio2 and FMOD Ex crap in today's games that treat headphones as one-dimensional left/right panning devices, and while it's possible for CMSS-3D Headphone to at least provide a virtual 7.1 mix with such games, native DirectSound3D and OpenAL still sounds superior by far because you're getting that true 3D binaural mix.
To make matters worse, Creative isn't really even trying anymore with these new Sound Core3D devices, which don't do OpenAL in hardware, and THX TruStudio Surround, which sounds much worse than CMSS-3D Headphone from a positional standpoint in my book.
I have a feeling that we wouldn't be in this rut had Aureal survived. They were the only ones to give Creative any significant competition in the gaming audio space. (Well, Gravis could have done so earlier if the Ultrasound hadn't been released at a time when game developers were already standardizing on the Adlib/Sound Blaster architecture...)
Until then, I guess we have to put up with games with graphics shaders out the wazoo that sound worse than games released in 1998. (That's when Thief: The Dark Project was released, and that series still remains my gold standard for audio design in games.)