A lot of people on this list have recommended the Sennheiser PX100 folding headphones, which made me curious enough to do a search for them on the web. Most of the websites selling the PX100's also sell Sennheiser PX200 headphones, which I think are $10 or $15 more than the PX100's. For the life of me, I can't figure out what the difference is between these two models - I would be interested if anyone could explain the differences between the PX100's and the PX200's. Thanks, Peter