I've got a pair of QC IIs, and mostly have been pretty happy with them. But they are v. bulky. I've been meaning to buy some Shure's or similar smaller earphones, but haven't had time to investigate brands, etc.

The Bose Customer Support were actually really great for me, because when my original (3+ year old) QCs were not working and it was very clear that "wear and tear" had something to do with their malfunction, they replaced my original QCs with QC IIs, for just $50.00