B&W will have better audio quality, Bose tends to be exaggerated towards highs and deep bass with an almost nonexistent mid-range (just like all the Bose home theater surround systems). Bose is NOT well regarded amongst Audiophiles.
The Bose have good active noise cancellation, but they are bulky on your head, so your level of relaxation is diminished somewhat. Also, the Bose active cancellation causes nausea and vertigo in some people!!
For noise cancellation, I like an in-ear design. Passive noise cancellation works better than active for stationary listening. Shure makes great in-ear designs with passive noise cancellation and fantastic sound quality.
If you don't care about noise cancellation, I really like the Grado Labs headphones. The Grado SR-80 is probably my favorite headphone set. It has excellent sound quality and costs a fraction of the price of the big-name brands. Grado is Real Good Stuff.