Grab a copy of "The little Schemer" (Daniel P Friedman and Matthias Felleisen) and a pencil and you can skip the phone and the notebook - oh and learn scheme of course.<p>Travel light but make sure you travel.
If I was a programmer I would probably pickup a Dell Netbook, install OSX on it, and use that as my learning tool. I appreciate your objective, but I think that calculator is a step backward. Maybe since I'm not a programmer, I'm missing something.
On a random off-shoot: is there something analogue (e.g. an abacus) that can be used for logic games or calculations that would fit in a pocket (and require no electricity)?