Some cool things about the iphone…
1) Location aware services + 3G data, local database storage and good API’s means that we’ll see a proliferation of applications that are contextually aware. I can imagine a todo-list application that knew if I was at the super market, at home or at work (Omnifocus is working on something like this). Or imagine a location aware blogging engine. Lots of possibilities for data analysis there and visualization using world maps and such.
I can also imagine a good ski-slope map application, hiking applications (including flora/fauna lookup).
2) Its the first handheld device I’ve used (talking with the 2.0 firmware) that fits as a logical extension of my desktop. This continues with MobileMe and the fact that it seems that app authors are treating the iPhone as such (such as NetNewsWire). With seamless synchronization, my phone is my consistent link back to my desktop. I can imagine services being made on the API to extend this further, such as the ability to run a remote spotlight search on your desktop computer and get results back on your phone, then being able to transfer a found file back over.
Or imagine location-slinging of content like video from your home, with transcoding on the fly. I could also see this link working for asynchronous data treatment. Take a picture, or note and assemble a package of information that is tagged (location, time, date) and waiting when you get back to your computer.
3) A lot of room for interesting art. “Where I’ve Been” etc. I like the possibilities of recording movement with sound and image. I can imagine you could assemble interesting audio pieces that way, or visual treatments of your daily movement. I wish I was back in art school when this came out.