Smartphones will eat the low-end, sure
...but there's reasonably limited scope for putting a big sensor in a smartphone (for lower noise, better low light performance, better tolerance of cheap optics, shallower DOF) or a big lens (for zooming, rectilinear ultrawide FOV, wider apertures) or even a nice big flash... so they won't be replacing mid-to-high end compacts or dSLRs anytime soon.
Similarly, there's not a lot of nice smartphones out there that would replace my GPS... IPX67 water and dust resistance, reasonably impact resistant, 40 hours battery life on lithium cells. Things like the Motorola Defy are getting there, but they're pretty niche and still not quite up to the job.
There are a whole family of unexciting bits of consumer electronics out there which no-one will really miss when they get eaten by smartphones, though. Dedicated car satnavs spring immediately to mind.