Well I personally don't have too much experience with closed-back headphones, but from what I've read, the Beyer DT1350 has some of the best noise isolation of any headphone (a whopping -19 dB according to Innerfidelity). Also, it seems that the AIAIAI is measured to be at -10 dB, while the HD25-i-ii is at -14 dB. The AKG K550 is also rated at -14 dB so you might want to check those out too.
Actually I went to an Apple Store recently and the new Logitech UE6000 has pretty good noise isolation (Innerfidelity says it's at -14 dB).
.....or you can try a Beats Solo HD with a measurement of -17 dB (no seriously they have terrific noise isolation, the sound quality isn't very good though)
Someone help me out here.
Does noise isolation refer to the user not hearing the outside world?
What's the term for the rest of the world not hearing the headphones? Leakage?
Edited by eron - 10/9/12 at 11:20pm