I bet games is the big exception here. I bet many of the "non-geeks" referenced by you and others in this thread have downloaded a few games to their iPhone, and would be much less likely to switch to a competitor that didn't have the same games or games that were just as good.
One more counter data point: at a party last Saturday in a room with a bunch of non-geek college kids, fiddling with their iPhones, one of them spontaneously asks "Hey, what's that app that can tell you the name of a song if you hold it up to the microphone?" One of the other college kids quickly confirmed that it was called Shazam.