Sennheizser is releasing a new improved model: PXC300 later this month. It has a higher level of noise reduction and an AA battery built-in noise reduction unit (not a clip-on thingies with special battery they have on PXC250. This will retail at around $220 and should be on par or better than Bose, which is supposed to be a standard.
I just recentl bought Aiwa, and tried them without noise reduction - the sound is very poor. I will be flying soon and will check them on-flight (which is their main purpose of use, after all).
Please note that these sort of headphones cancell only static constant noises, mostlyin the low-to-middle frrequency range (such as airplane/train noise, etc.), and will not significantly cancel random noises.