What can I say about the iphone 3g that hasn't been said. All I can say is I want one and I want to develop on it.
The one thing that sold me was the true GPS support. This thing is going to herald in the geotagging revolution that has been conspiring in dark rooms for a couple years now.
Just like podcasting which hadn't taken off until iPods took over, the iphone is going to do the same for geotagging.
We're going to be geotagging everything. I'm anticipating some really awesome apps based on gps.
Remember http://www.dodgeball.com/? Awesome idea.... Now think of dodgeball.com on the iphone with gps, a perfect idea.