[Astronaut]

I agree with your point about reliable broadband internet. Until that happens, a PDA is just a very expensive address book. Even though some people constantly clamor for it, Apple has wisely chosen to stay out of the PDA market, even though they invented it with the Newton over a decade ago.

[Cosmo]

I'm betting Apple will come up with a hybrid PDA/iPod fairly soon.

[Gamecock]

a PDA is just a very expensive address book

I must disagree. While they do function very well as an address book and appointment calender, that does not even scratch the surface of what they are capable of doing.
I use mine to track patients, store medical books and drug references. (meaning I don't have to carry heavy references around in my lab coat) With the attachable keyboard and a Word emulation program, I can type memos, and take notes in meetings.
I can hot-sync in the morning and have the lates news downloaded to read at my leasure. I always thought I wanted a laptop, but they are, IMHO, not portable, but transportable. My Visor offers true portability.