Minority Report style computing has existed for a long time now. I was doing a research internship a few years ago and was talking to one of the professors about it - the Minority Report interface was based off real interfaces, not the other way around, and these interfaces were rejected as useful means of interacting with a computer because its much too tiring to wave your hands around like that for long periods of time. At least, this is what I was told.
Having said that, I'd love the three projector setup at the start of the video that mrphoebs linked. I also imagine this kind of thing would be awesome for entertainment (more awesome wiimote) and it looks like it could be useful for some specific tasks too.