I've been very happy with the Bose headphones, however, I would make a few comments. Firstly, they're expensive, even if you buy them in HK or claim the GST back from them. Secondly, they're designed specifically for use in environments with a certain level of ambient noise, and not designed for use in quiet environments. Thirdly, they're reportedly fragile, so I've had to take care and not trash them.
That said, they're great to listen to movies and to music. What I've found is that the noise reduction allows better appreciation of classical music and more subtle music. On a 744 they were great, with pretty drastic noise reduction. On a twin prop, there is still a residual level of noise, but much, much less than usual. On removing them, you notice your eardrum muscle tense. Also used them at the gym, which was great.
Overall, very pleased. They are bulky, admittedly. They come in a carry case which is larger than a thick paperback, but I guess you don't need to use the carry case if you prefer. What sold me was going to a Bose store with my iPod and plugging them in. I was immediately sold.