For those interested in non bose options then i would offer up 2 alternatives. A cheaper option yet still with great noise cancellation is the Audio Technica ANC7, can be had for about £100 if you shop around.
http://www.amazon.com/Audio-Technica.../dp/B000OMKR8E
My recent purchase that i'm extremely pleased with is one for the gadget lovers called Parrot Zik. The noise cancellation is not as "powerful" as Bose however the bluetooth, touch sensitive , motion control , NFC . etc more than make up for it . pricey tho.
http://www.t3.com/reviews/parrot-zik-review