The HD 800 in my opinion proves there is plenty of life (not just about staying alive, many feel they are far superior to the LCD-2 etc) in dynamic drivers. And the HD 650 is still fully competitive (with a good amp) with many high end headphones. As a large company I see little point in Sennheiser going electrostatic, the market for those is just far too small. The HD 800 has sold pretty well too, I´m sure a lot better than the electrostats they used to make. Magnetic planars, it would indeed be interesting to see what Sennheiser with good resources could do with that tech - let´s be honest here, so far planars have more or less been made by garage type companies (compared to Sennheiser).
However, I see little point why Sennheiser would move in that direction after investing in proprietary tech to have the best soundstage in the headphone business (HD 800 patented ring drivers). Going planars doesn´t fit the Sennheiser house sound at all... My bet for the next Sennheiser high end headphone is a revised 650 with the new ring drivers. Something like a HD 750, in the 500-700 $ price segment.
Edited by vrln - 9/19/11 at 1:48pm