Telex 50-D is hands down, the quietest. Pretty comfy too. The Bose is a lighter if it fits you, but no where near as quiet. I wear the 50-D on a regular basis. Added benifit is the anr works on batteries, or just plug into the cig lighter in 99% of the planes you'll fly. The passive only noise reduction is about as quiet as the rest of the anr stuff on the market. And to top it all off, it doesn't act like a vice clamp on your head for that noise reduction.
if you are looking at dropping $1000 on the bose, do yourself a favor and try the top of the line (and the level below the top) ANR headsets from all the major companies (you'll find other brands top out around the $500-700 range). That's what I did for hours in each, and the decision is then very easy to make.
I've current students with the Bose, and the DC, and Lightspeed models. All the high end stuff. Love to do the swap test with them. Makes a sad look on their face though, every time, when they realize how quiet things can be. If you are willing to spend a lot, go for the best, not just the most expensive, or the one that is the most common color.