TrustedReviews posted a review of the Creative HN-700 - Noise Cancelling Headphones
Obviously the big question is whether the noise cancelling works or not and I’m glad to say that it not only works, but works superbly. I did a little test in the office by standing underneath the air conditioning unit - this is a particularly noisy bit of kit that produces a similar kind of rumble to the engine noise in an aeroplane. Flicking the noise cancelling switch on the HN-700s completely eradicated the noise, cocooning you in an ambient noise free zone. I also tried them on a tube train and although the bangs and clacks still broke through, the ambient rumble was completely gone, allowing you to listen at a lower volume level.Creative HN-700 - Noise Cancelling Headphones Review