Smartphones are indeed fantastic versatile devices, but there still is one important feature missing from them: payment. There are payment methods based on SMS, but they are limited in scope.
Payments have been moving away from cash for about two decades and therefore payment terminals have had to be exchanged once in a while. That's costly for small traders, who aren't keen on ever fancier payment solutions. Consequently, the smartphone as wallet is not going to happen very quickly. I expect within seven years the smartphone will be as good for payment as a credit card is now in 2012.
When cultural history is written in about 50 years, I think the smartphone and the pad-computer will be seen as particularly important devices, the devices that changed the world. Wireless technologies will be seen as the enablers that made the lift-off possible.