Graynomad:
I think I'll stick with Arduino, the RPi looks nice in many ways but it has too much of what I don't need and not enough of what I do.
Very well put. If only the RPi had some ADCs and more GPIO, I think it would dethrone Arduino as the microcontroller king. RPi has nailed two very important aspects that made Arduino great: 1) Price and 2) Grass roots exposure at schools & colleges. I'd say the exposure has been viral & global & immediate.
With ADCs and more GPIO and better documentation, RPi can do to Arduino what Arduino did to Parallax basic stamps.
One clear advantage RPi has over Arduino is the programming language. If I could choose any language I'd choose Matlab script or Octave because of the vector programming power over matrices. That's a pipe dream of course. My second choice would be Python, RPi's default language.
I will be watching RPi closely. In the meantime, I plan on buying the 32bit "Due" when it comes out in October (my prediction). It'd be nice if someone found a way to link the RPi to the Due.