I actually did a bunch of research and testing for a friend when he was looking for full-size, noise-canceling headphones for the train.
As far as widely-available headphones go, Sony and Bose were pretty comparable with Sony tending to be slightly cheaper. I personally like the Sony NC60 the most as the NC500 didn't really offer a whole lot more for $100 extra. The NC60 was comfortable, fairly sturdy, canceled out store noise really well and $100 cheaper than the closest Bose model. The only problem was I can't comment on sound quality.
Though I'd agree with Sherwood and if you can find a used pair of QuietComforts, they were easily the most comfortable.