The first wave are the tech enthusiasts, these people are not big app buyers but are interested in finding a good SSH tool, or an mail client that supports PGP. These were the main customers of the first iPhone.

I'd say we've been in the second wave for the last couple years. These people are seeing TV the ads and are curious. Their friends buy iPhones, it makes sense for them too as well. They're not "hackers", just people that are willing to try apps. These are your Angry Birds players, and where the main revenue comes from.

The third and final wave will be moms and general folk who will never sync with iTunes. It's those people that are never going to buy an app because they won't know what an app is. And that's fine, they'll like how their phone talks to them and how they can Facetime to their kids.

I don't mean to say that all iPhone 1 users are "hackers", just that a higher percentage of them were than are now iPhone 4S users. A lot of those people likely went off to Android in the recent years, anyhow.