@save2600
I think your too pessimistic about what could be done, even if right on the money about what will be done. What the Amiga did in it's day (obviously) wasn't impossible, but was shocking at what it did in it's price range.
So, take a look at it from that perspective. If someone could put together a system that had the things we can do today at huge prices, but could do it at less than a grand, what would we have? I know that I have been waiting for a game cube. Not the box that Nintendo put out, abut a 6 walled room you could play in with displays on all sides. Maybe we would have to settle for the floor not being a screen, so 5 sides, but we have the tech today to put up a 8'x8'x8' fiberglass framed tent with walls made of materiel designed for projecting an image from behind. 5 projectors, and we have a fully immersive environment for starting this new ground breaking system. Maybe it could be improved by making it a dome, and have software distort the display properly so that it looks right from the inside. Now, had some motion sensing cameras that have better response time that MS's, and you have a gaming environment, and actually a work environment like you have never seen before.
A similar effect could be achieved with stereoscopic glasses. 3D TVs will find their niche in video gaming (I don't think they will in watching television), but it is really the wrong approach for 3D gaming. Monitors fit inside the glasses with a left eye and a right eye image would make a lot more sense. Again, fitted with motion detection, you would have a whole new gaming environment.
Neither of these would be are outside the scope of what we could do today.
For more businessy type stuff, how taking the above game cube and making it the office cube. Build in a really good real time video codec (liklely in hardware), and make the cube your office cubicle. A couple of these in the office, and you could have face to face meetings just like you were there. You would get all of the same audio and visual cues without the long commute, as you would be sitting or standing right next to the person you were having a meeting with. Heck, put in a little fake Segway in the corner, and you could cruse around the entire office. Would a system that gave you a 'Virtual Cubicle' networked with an entire office of 'Virtual Cubicles', 'Virtual Conference Rooms', and maybe even 'Virtual Lunch Rooms' be any more difficult engineering wise, or any less ground breaking than what the Amiga was when it was released?
All that being said, I still think that making stuff happen physically is the 'PC' of the next decade. Robotics has just gotten cheap enough to be a home hobby for the nerds. We are at the robotics stage of the early computer kits. We are just at the verge of the Vic20 stage of robotics.