Have headphone earpieces swivel to listen horizontally
I LOVE my Image ONE headphones. And one thing I like to do before going to sleep is laying down in my bed and listening to music. When you do this and have the earpieces correctly in place, the piece that goes over your head jams into the pillow and places pressure on your head, making it uncomfortable. If you get the headpiece off the pillow and almost to your forehead, then the earpieces don't fit right.
I think it'd be a nice feature not only for this, but for DJ's who like to wear the headpiece around the back of the neck.