iPodTouch, the next generation of iPhone users...
Yup, that's how I ended up with an iPhone. I bought an iPod Touch when I was traveling a lot, and wanted to be able to watch movies on the plane.
But, since it has all the software of the iPhone (except the stuff specific to the phone), I was able to see how well the email client (IMAP, Exchange integration) and web browser worked, I decided to upgrade to the iPhone.
I waited until the 3G came out. Then, I sold my iTouch. The iPhone is by no means perfect, but it's better integrated and more functional than any smart-phone I've had.
I have one. It’s great!