Can you imagine how the world will change, when people can truly walk around with their personal libraries with them, carrying tens if not hundreds of books, without 1. Internet access, 2. hauling a heavy laptop, 3. hauling any device where the battery dies in approximately 4 hours of usage? Reference books, technical manuals, fiction, non-fiction, comics, you name it, anything can be handily carried in your pocket, as if you were carrying a paperback book.
Just look back a bit think how portable MP3 players created a new kind of cultural phenomenon. Sure, we had Sony Walkmans before, but back in the days there never was such a massive amount of diverse music available for the portable players at such low cost. Today, an OK MP3 music player with tens of hours of playing time costs something like few tens of euros.
At the moment, a similar phenomenon is about to arise in the form of electronic book readers. Such readers utilize e-paper, which is a display technology giving more or less has the graphical "look and feel" of paper. Electricity is spent only to update the display, not to keep the existing picture intact (unlike LCDs, TFTs and other such display technologies) - this translates to very low power consumption.
There are nowadays many such devices in the market. Personally, my greatest interest is towards the Bebook reader (I haven't yet bought it). Also, the Sony PRS505 seems interesting as it has a touch screen which makes it easier to make notes and annotate things. There is also a bigger list of e-book reader gadgets at Wikipedia.
Currently the screens are black-and-white, and can't be updated as fast as, say, LCD screens. But I heard it through the grapevine that this will change soon with the introduction of super-thin, transparent, e-paper screens which can do color too. (Carbon nanotubes, is there nothing they can't do?)
Once those e-book reader devices truly take off, the result will be that much more people will be reading books more often than before. Also, books which have been "forgotten" will have a new life as it will be easier to read them not just sitting at your laptop, but anywhere you go. Even if you're on a budget after buying a fancy e-paper reader, you still can find quality reading and many, many classics. For example, there are a lot of Project Gutenberg books (i.e. books which have their copyrights expired).
As I consider reading (quality) books, learning and immersing ones mind in new thoughts and new perspectives to be absolutely beneficial for the individual, I can only see huge benefits with this cultural phenomenon which will increase dramatically the "consumption" of books. In fact, I think in the long term this new "library in your pocket"-phenomenon will have the equivalent effect of dropping a black monolith in the middle of a gang of apes.