Mono is monaural, like what you'd get out of a cheap TV with one speaker.
Look Ularewolf, humans have two ears. That means there probably isn't a huge difference between stereo and multiple drivers. Theory is that the drivers are so close together that making out separations in sound would be difficult, if possible at all. I sure wouldn't like to be playing a game and devoting all my attention to picking out the .0001 cm difference of a sound wave.
You seriously are on the wrong forum, as the Koss Pro4AA's truly aren't high end. Lots of gamer websites will rave about this headphone or that... not many have heard true high end sets. I've been in your boat before, checking out the 5.1 headphones, but I didn't buy into it. I thought a lot of the people here were insane, spending so much money on headphones. The A500s I own were about $100 from audiocubes and that I thought was the absolute limit for me. But... I was wrong.
Now I have loads of stuff. Remember that I haven't auditioned a single piece of equipment in my sig, so I guess I come off as a bit impulsive. But it really was worth it. Now when I listen to cheap headphones like the Koss ones or Sony streetstyles, the difference is instantly evident. Not to say that the Koss line is bad, they're excellent for the price. But they're just not as good as a lot of other headphones.
I'll tell you now that not all 3D audio systems are created equal! Your integrated sound will sound like trash, it's a given. No integrated sound is good (including soundstorm). Stereo will have inherent imaging, thus 3D audio is not always required. If you must (like me) then Yamaha Silent Cinema and Dolby Headphone are really your only choices.
I honestly think you should be more open minded. Although you say that you value all of our opinions, all of your replies have been shooting them down. Not all things are created equal! I cannot stress this enough. There isn't some sort of generic 3D audio algorithm or some generic headphone design that applies for everything.
Theres a whole world of higher quality audio out there and if you don't want to get involved... thats fine. You could never return to head-fi and enjoy your 5.1 headphones, but I think most of us would want to let you know that theres BETTER for the money. With your apparently frugal nature, I think that you'd like to get the best bang for the buck.
Your so called skepticism seems to be rooted in defense of your headphones... perhaps a regrettable purchase? At any rate, technology is also not everything. Perhaps I can put it in different terms... A Geforce FX5200 has the technology to play the game. Does it do it well? Nope. While looking for an upgrade, are you going to get the bottom of the bucket video card from the new line that can do pixel shader version 509093?
Finally, I'd like to wrap up my rant by saying that there is simply better for the money and a lot of people here would be happy to help you. All you have to do is let them.