There's a difference between a device that can do the job and a device that you prefer to use to do that job. I prefer my android phone to a netbook, because it has the phone part, and because netbooks which are near it in size don't have typable keyboards (for me), so I'm not losing that much.

A friend and I were talking about this recently, and he mentioned that he'd love to just carry around a single device that he could use for all his computing, but that it would have to have all the features of an iPhone or G1, plus the ability to use a regular keyboard, mouse, and screen when he was at home. With such a device, a laptop that was basically just a peripheral bed for the phone/device would be useful, as well, for that typable keyboard.

I think we're almost there, but not quite. The requisite features could be built into current-tech devices, but aren't, at the moment.