I would love to be able to use a Bluetooth keyboard with the iPhone. My wife uses and external keyboard with her Palm*all the time - very nice.
But those external keyboards suck. They bend in the middle, you have to make sure they have batteries, you need to balance your palm on your leg or lean it against your coffee. If you're going to have an external keyboard, you might as well have a 12" laptop. (That said, the Dopods and Oqo's get close to solving that issue.)
The fundamental problem with handhelds is input. It's slow and awkward to input text to them. You have to either write it, or select keys from a display, which is seriously slower than using a keyboard.
Look at Steve during the keynote and he's slow on the text. Fine for SMS, but it sucks for Mobile Pages or email.
There was one solution to the whole issue of portable typing called the microwriter:
http://en.wikipedia.org/wiki/Microwriter which allowed almost full typing speeds for mobile input, but you had to learn a whole new way of typing.
Dasher (
http://www.inference.phy.cam.ac.uk/dasher/) looks good too, but takes up space on the screen.
I've had palms for ten years and I can only input at a fraction of my typing speed. It is far quicker to type into my Mac or PC and then sync the palm. I have a palm T|X with 2GB+ of storage. Why is it such a pain to write a report or even a letter on it? It's a 300Mhz processor, far faster and more powerful than the 1Mhz BBC micros and Apple ][s I used to write reports on way back when. Why is it harder to write text on this than the Apple ][ I had in 1980?
Whoever solves the problem of high speed mobile text input will win the PDA game. The future is a pocket sized device that allows you to type at full speed with one hand. The company that brings that to market has won.
When I can stand up on the bus or train and one-handedly write text at my normal typing speed, the input game is won. I hope it's Apple, with multi-touch. It won't be Palm, as they've given up. Microsoft don't innovate, so it won't be them. It may be someone new.
I hope it happens soon.
Before the jet-packs and flying cars.