I use it for:
- Contacting family and friends (phone calls, SMS, iMessage, Facebook messenger, etc)
- Internet banking (especially moving money between accounts)
- Music (Spotify, Pandora, TuneIn, iTunes), and increasingly podcasts
- Camera (having a decent, portable camera is useful)
- Taking notes
- Reading news/web pages on public transport
- Facebook (blah)
- Public transport timetables and the Tramtracker app
- Having a full QWERTY keyboard instead of that god-awful multitap
- Weather forecast/information (usually using Ozweather because the built in iPhone one doesn't get its weather data via the Bureau of Meteorology)
- Keeping up with cricket scores
- Shazam
- Maps (biking maps in Google maps are pretty useful)
It's pretty bloody useful, and now I'm out of contract using a cheap MVNO, quite cheap (especially considering I don't have a landline, landline rental is too expensive)