Been putting some serious time on the AKG K271's, so I think I'll move them up a rank. The ranking now being:
3. DT770 Pro 80
The more forward mid range on the K271's make them good for low level listening and noisy environments. I recently flew (for the first time!) and brought the K271's, and they worked very well. To be honest, I expected planes to be louder. I think pretty much every car I've ever rode in was louder (or at least had more low-frequency noise). The isolation on the K271's was really nice for this, and really, I think the isolation on the CD900ST's would have be sufficient for the plane ride.