Nicholas Negroponte is best known today for his work with the One Laptop Per Child project, but he's been doing interesting and pioneering technological work for a long time. In 1984, Negroponte gave a talk at the very first TED conference. His talk was about how people interact with computers, both in the present (in 1984!) and his hopes for the future. Negroponte's discussion is surprisingly relevant to modern technology; his view of technology from the very early days of the personal computer focuses on the human side of the equation rather than the technology itself, and that human element hasn't changed much in twenty-four years.
For example, Ngeroponte talks about touch screens (now popular in the iPhone) and criticizes Apple's then-new Macintosh computer's use of a mouse -- he argues that Apple would be better to rely on touch than a mouse, because "you don't have to pick up your fingers in order to use them." He also points out that fingers are a lot higher-resolution input devices than mice, and "you have ten of them!"
It's a great talk -- intellectual, funny, and prescient. It's also pretty neat watching him use a totally high-tech Laserdisc player to illustrate his points. Have a look: