Too expensive for casual listeners and too bad sound for audiophiles. There are much better choices out there.
I bought them 18 months ago and have virtually only used them on aeroplanes, because their sound is outperformed by any other headphones when you don't need noise cancelling. And when it's noisy outside, they work but don't cancel as much noise as you would expect. Sennheiser's CX300 will be almost as good for a little fraction of the price. If you want really good noise cancelling you have to spend much more money which I would say is not worth it either. Better fly business class and have them borrowed from the airline.

These headphones do half of their job; exceptionally well.
They indeed block out all noise 85%; and I have a neighboor, who is home 24/7; playing loud bass TV/Video Games; with child on weekends!

The problem #1 The Audio is not what it should be at this price (sometimes as high as ($200.00)
At a frequency response of: 14 - 22,000Hz, while blocking out all outside noise these headphones, cannot take even the most basic; bass sounds and they distort. Compared to the bass you get out of Sony's V-600 5-30Hz (Regular over the ear non noise canceling) these are a joke!
And just try calling Sony to get a replacement parts; for this brand, or any brand for that matter. In 2009, it would be easier to find a job; then getting Sony's attention on this matter.
Audio-Technica’s ath-anc7 has already sent me 4 replacement parts for my 2 pairs of headphones, and even though these have a Frequency Response of: 10 - 25,000 Hz; they sound better then the V-660s Sony’s do; as these, put the sound closer to the ear, and the bass booms at a decent volume too.
The Sony V-660s have to be literally pressed with both hands against your ears to get optimum bass!!!