After seeing your other responses in this thread I'm going to add the following items for you:
- Friends
- Soap
- A girlfriend
- The common sense God gave a duck
I seriously laughed out loud. Well played, sir.
To put this back on topic, some more:
- Metronome (my sister plays high-level piano with a Metronome app)
- Thermometer (sorta?)
- Radio (sorta?)
- Bar code scanner
- Credit card scanner (with accessory support)
- Laser-level for construction
- Weight recorder
- Diabetic thing
- Gym log
- Gym exercise chart
- Blood pressure recorder
- VoIP
- Portable DVD player
- One of those solely used for email devices
- Text book (I have my text book saved to my iPhone)
- Todo recorder
That's just some off my head.
For the record, in regards to word processing on the iPhone, it's certainly doable. It by no means replaces a laptop, I'd take it any day over the iPhone for word processing, however in the case where I had to type like a one page report, and I lacked my laptop and had my iPhone with DocsToGo on it, it might be a bit tedious, but I could definitely do it, and hey, I have. It's actually quite convenient for other languages with the easily addable accents. You could edit a document as well.
So yeah, we'd all prefer a laptop or normal sized keyboard in general, but the iPhone could do it if you had to.