Kindle and the Nook, are great improvements over earlier generations of e-book readers. Both the price and the technology are at a point where the devices are becoming truly accessible and popular.
There are lot's of implications for libraries of course, and this article at Publishers Weekly, a library trade magazine, gives a nice summary of the current e-book scene. A good read for anyone curious about where all this may lead to. Your blogger would like to emphasize a key point that the article makes, namely that libraries don't simply collect that which is currently popular. Libraries, especially college libraries but also the larger public libraries, collect on a broader basis that just that of popularity, and then they preserve that which they have bought for future generations. Like the article says, there wouldn't be a Google Books if libraries had not assembled and preserved all those books over the generations!