Apple's famous Knowledge Navigator video can be found online (needs QuickTime), and there's also a piece by Jon Udell on it and where we are today. For a 1988 look at an information-centric future it's surprisingly accurate, and we could acually build most of the elements in the video with current web technologies on a - though we're still a long way from its natural language interface!
This is one of the clearest examples of the visionary thinking from so many different people and companies that inspired me to work in IT. Others included reading Ted Nelson's Dream Machines at an early age, and Scientific American's 1992 special edition on the future of computing. I still come across ideas that inspire me, like Microsoft's Forum 2000 scenario videos - especially the "Steve Masters" distributed computing piece.
Perhaps we do still have it in us to change the world.