Those are pretty different headphones.
The 701 would be the logical progression from the 272, if you like them and just want an upgrade. Of course, then you have to ask how much are you really upgrading going from 272 to 701. I'd say enough if you know you like the higher end AKG sound.
The others are drastically different headphones. Senn 600 are a dark headphone, which isn't a bad thing, but you may not like them at all coming from AKG. Their weight, sound-wise, and general musical texture can me mistaken for sluggishness and muddiness if you don't get into the sound.
I don't know much about the Denons