Most of us think that headphones is a niche market. Well, in some ways you're right, and in some ways you're not.
The company I work for, Electronics for Imaging, has at least 1400 people worldwide, I say 500 of these people have headphones in their offices. On one floor I've visited, in one area, 4 people had headphones in their cubicle. These are the phones I saw in the area: Grado SR60, Senn 580, Sony MDR-V700, and Philips HDxxx (sorry not familar with Philips headphones).