I already own a pair of Sony MDR-NC60 noise reduction/noise canceling headphones. The sound is very good, the noise reduction is pretty good. They are terribly uncomfortable on my huge gourd, however. And when I'm wearing glasses (most of the time) they give me headaches as they pinch the earpieces into my skull. I'm definitely in the market for some new NR headphones; I travel frequently and find the NR feature very nice on planes.
I borrowed a pair of Brookstone NR headphones, and I can report that they aren't any better. They are far more comfortable, that much is certain. After prolonged wearing, they still cause discomfort around my ears as they pinch my glasses into my noggin. I think the NR feature is better on these as well; they seem to cancel noise a bit better. The biggest problem is the sound; these are so quiet! I have to turn them up significantly, but in doing so the bass is increased, forcing me to turn it down. They just aren't as clear as my Sony phones. I'm going to return these and keep looking.
I have a feeling that I'll wind up with some Bose phones. I know they are terribly expensive, but I also know that they're far more comfortable than either of these sets. And I know the sound is much better than these Brookstones.