'Celia, Celia, Celia... .'
http://www.youtube.com/watch?v=k6bkmPjVF-k
Who knows what screen-tech the future will bring? I suspect eink will look very outdated quite quickly, although it will be a long time before it is actually surpassed for pure reading comfort. Most people will prioritise convenience over sheer quality anyway.
I suspect that at some point screens will become so ubiquitous and disposable that your morning coffee mug will have a display on the front that will not only tell you the temperature of the drink, but show you that morning's news, too. Such a tech will see R&D yen because it will appeal to everybody, not just readers.