I am currently on my iBook, and that usually means listening to music on one of my headsets. It just dawned on me why I really enjoy the sound of some of the Bose headsets.
Almost all the listening I do on a headset is at low volume. The extra bass presence at low volumes helps to keep the sound full. Of course, the fact that they are exceedingly comfortable does not hurt either. I can wear the TriPort OE (or QuietComforts when need be) seemingly forever before they become uncomfortable.
They are not the most detailed, but the comfort and bass presence makes it easy to enjoy music at lower volumes, without the uncomfortable feeling of other headsets I have tried (including my Stax IEMs).
Yes, I also have the TriPort IE as well, but my fiancee has taken those over for use with her iPod at work.
I've tried them in a store, and one of the players on my basketball team has a pair. I'm not a big fan. They sound decentand are comfortable, but they don't do a good enough job keeping sound out IMO.
Have you tried IEMs Nuck? They take a little getting used to, but they block out so much more sound, and are a lot more convenient from a size standpoint.
Using uncompressed music, my Etymotic ER6i and iPod sound very good.