For all the talk of new energy sources -- solar power, hybrid cars, wind farms -- the fact remains that not a single jet has been designed to fly on anything but jet fuel. I'm sure the same is said of many similar energy-reliant products. So although we are (thankfully, belatedly, mercifully) headed towards renewable energy sources, the oil and natural gas industry isn't going to disappear in my lifetime. Will it change? Absolutly. Disappear? No.
I think the same holds true of books, and for that matter, libraries. They will not disappear, they will continue -- but in a hybrid fashion. As evidence, I have yet to work one day in an empty library. Ever. But looking around, the view is certainly different from the libraries of my youth. Most obvious are the computers. Some would argue that's not what libraries are for. But look at what people are doing on those computers: reading, researching and playing. All that stuff libraries were designed to help people do. Is some of it fluff? Junk? Sure it is! The same could be argued about many books in any given library (*cough* especially near the paperback rack *cough*).
Libraries were, are and will always be places of knowledge. How we receive that knowledge may change, but our need for knowledge will not.