Brilliant. This is what I have been dreaming about for years!
PCs are not sci-fi, they ARE indeed like trucks. What you say and what I dream is where PCs should be heading toward.
One small tablet device to go but it's "2"... whenever you need the full horse power, you just attach it to a monitor or make itself bigger and you play your games on it.
That being said, I think we are heading in that direction already but almost... with RemoteFX, maybe stuff like http://thinlinx.com become a little tablet in your hand where it can use the power from the server and just stream the stuff. Kind'a like "OnLive" http://www.onlive.com/ ...and this way, we will soon have both a small good to go tablet and the full PC as long as you got a good line ofcourse.