Being at home on a rainy day, but wanting to read some new novel that just came out, you can have it in seconds. This concept (not hobbled by DRM) is pretty damned liberating.
Ebook readers have extremely high contrast/readability and are extremely energy-efficient, being able to display several thousand pages of material without needing to recharge. eBooks are a narrow product, but they have their own ways in which PMPs cannot compete.
Typically ebook readers are larger than PMP's with larger screens. If you're going to read for a few hours, then the screen of a typical PMP becomes pretty eye-straining (due to size, contrast, and brightness).
As glued to the net as we all are, there's vast quantities of content that is not available online.
A revolutionary portable reader that wirelessly downloads books, newspapers, magazines and blogs to a crisp, high-resolution electronic paper display that looks and reads like real paper, even in bright sunlight.