It's a ME type era. Well, as someone who was raised to know better, I don't know how we tolerate this type of rudeness. I believe its time for a change. But if two people take out their Pilots and are beaming information to each other at a dinner, that's more acceptable to me because it's social. In private situations, such as riding the subway to work, waiting for your plane, sitting at the bookstore, or waiting in a line, it is fine to use your handheld for whatever it is you use it for.
Public situations are different.
It can be distracting as well as just plain rude to others. Yes, it has LOTS of cool functions and features. Yes, it is a lot of fun to use. No, it's not polite to flaunt it in front of others. One, they just may not care.