Interactivity will become increasingly important as well. I think we'll eventually see ways to interact with books that no one had thought of before. E-ink displays like the Kindle and the Sony Reader will therefore go the way of the dinosaur. They are great for daylight readability and low power use, but they are too slow!
It would be cool if e-books made it easier to read in foreign languages. In a language that I mostly but not entirely comprehend, I very often want a translation or explanation of a word or passage. Reading a real-world book with a dictionary at hand is a huge pain.
What about a "translation mode" where every time you pointed at a word, there would be a pop-up definition. Probably also enable swipe-highlighting a passage and getting a translation as well.
