I like the idea of the iPhone - a device that combines a cell phone, iPod, camera and wireless internet connectivity - and I'm sure this type of device is going to be standard in the future.
Essential to the usability of the device is the full featured internet - what you see on your computer you apparently can access on the iPhone, including maps.
While I would love to have an iPhone, I am going to wait. Why? I'd like to see the bugs worked out by other people before dropping big bucks on a new device. If past behaviour is any clue, Apple will be innovating and releasing updated iPhones at a regular, steady pace.
Another reason for waiting? I probably don't need all the functionality at this point. When I lived in Seattle and spent a lot of time running around, it would have been useful. Now that I spend 90% of my time working in my home office, the features are "nice, but not necessary". However, I'm still going to hold off a year before replacing my laptop (which crashed before Thanksgiving). If an iPhone type device can be used to access Exchange or Sharepoint, it might make sense rather than buying a new laptop.