I have active noise canceling headphones and active noise cancelling earbuds, but I find it hard to sleep in either. I always bring a pair of Hearos ear plugs. They are cheap (there are several versions and sizes) they are soft and they are the only ones I can sleep in. They do pretty good job of cutting down the noise on and off the plane and are the most comfortable of any I have tried.
http://www.amazon.com/Hearos-Ultimat.../dp/B001EPQ3H4