Sony MDR-7506 Headphones
There's a reason why you see these headphones in every movie, TV show, and music video where the director or sound guy is shown. They've been the industry standard for years, and they still can't be beat for the money. If you're going to spend $100 on headphones, it better be on these. Forget noise canceling and earbuds and Bose, these are better. Try them out - everyone I've recommended them to has been instantly hooked.
Everyone needs a pair of these to work and be absorbed in the music.