I got my iPhone handed down after my mother got it free on a heavily discounted contract. She upgraded to an iPhone 4, then my dad followed suit.
I love the iPhone. A friendly user interface, fast working, quirky apps and real music tools. I use Notes to email myself and record lecture notes, it's a voice recorder and dictaphone with text-to-speech software. It has handwriting recognition, I practice my Japanese on it. I use the calendar to keep track of my hospital appointments. I use the camera and photobucket app alot, and it's easy to email myself photos of work I need to print out for grading. I use google maps several times a week, the train timetable and route planner have saved my ass many a time. I can check facebook quickly, do online research as soon as the topic of interest comes to me instead of firing up the PC. My wifi signal is awful but my phone picks up the signal more consistently and stronger. Our teacher regularly sends us announcements and assignments via email or Dropbox, both of which I can access anywhere. So many times I've used my confirmation emails and QR on the iPhone to collect tickets when my printed Proof of Purchase didn't work. I have an app that can find me any establishent I specify (like a particular shop or the nearest toilet) I can shop online, like I bought my university equipment as they told us what to get on enrollment day. They're good for data tanager and reading your favorite books/articles on the bus or whatever.
It is a powerful tool that is a real help to me with my dyslexia/VPD and general constant navigation failures.