Simple thought today: a USB mobile phone. So you could just plug it straight into a laptop or something, without bluetooth or infra-red. I think Motorola tried something like this with the timeport 280 and also the A920; but I never learnt whether it was much of a sucess (unlikely given earlier timeport designs).
Better yet if the phone could be charged and synchronized over the usb cable while connected.
Obviously that doesn’t mean that I don’t like bluetooth any more, I’m still very much in favour of bluetooth. But now I like USB as well. 🙂