One of the biggest drawbacks of headphones is that they block oxygen supply to the ears. Hence when you use them more than a few hours a day you start getting ear related problems. So my idea is a head phone that won't give you any problems, even if you use them for 8 hours+ or more ( you know people in the service industry call centers etc , basically those people who are not audiophiles.)
These head phone will have two modes, simple (no amplification) and powered mode (sound amplified by an external source). Now the most important part . These will be absolutely non contact head phones i.e they will not touch any part of your ears. The mounting will have to be designed in such a way that both the speakers hang tightly near the ears without touching them. The head band will lock on the head over the ears and by using a special adjustment meter, the user can define the distance of each speaker from his ear lobe. Once the adjustment is done, the next time the user just wears the headphone and they fit exactly at the place where he wants without touching the ears. Have you tried this? Just take two speakers very close to your ears, don't touch them and listen to the rich surround experience that you get and your ears do not hurt. This is what the new head phone design will offer.