I have had my Yamaha RH-5MA open headphones for a long time now and I love them. When I first bought them, I had to quickly make a return for a new set because the original made some kind of faint snapping sound whenever the headphone played some bass.
I am hearing more and more about noise cancelling headphones. I went to a Bose store, which is inside a very noisy mall. Perfect setting. With no music playing, the noise cancelling blocked out 90% of the sounds including an annoying hum. The music did sound very good, but I was unsure of the source of the signal. They collapse nicely. The product materials feel cheap.