Confession 1: Soon as the App Store opened, I started downloading. Free apps mainly, but I bought more than I thought I would as well.
Confession 2: I don't use most of them regularly. I mean, I use the built-in apps all the time, daily if not near-constantly in the case of Phone, Mail, and Safari. But the App Store stuff? Eh.... A couple have become regulars but most are occasional at best and some I no longer even bother to store on the iPhone (i.e. they've been relegated to iTunes purgatory.)
60 million downloads, 30 million in sales, and Steve Jobs thinks it could be a billion dollar business. So somebody must be using them, right?