On the other hand, although I love my phone's portability, there's no substituting a few hundred watts of processing power and a few terabytes of storage in a decent desktop.
I guess that's my point, in a way. I've got my phone everywhere, but its utility is inherently limited by its power. My beefier machines are powerful, but inherently mobility-limited by their form factors. Plugging the phone into a dock or something increases its I/O abilities, but doesn't give it the extra benefits that make the non-portable computers useful.
> and peripherals are ubiquitous.
I'm not sure what you're specifically thinking of, with that. I know that I've got many more PC peripherals than phone ones.
I mean "I can take my phone most places and expect to find both a HDMI-capable display and Bluetooth input devices." Of course, I don't expect massive computing power - but even as a thin client to more powerful machines, this would suffice; and always having a netbook in your pocket is also useful.