When the iPhone came out I resisted because of the extremely expensive data plans here in Canada (presently $85 a month for 5 GB). Initially, I couldn't see any use for an iPod Touch, but once I had bought one, I couldn't live without it. I use it for daily tasks; I use it in my business for information I need easily at hand (including audio tracks); for email when I am at the university, and much more.
At the moment, I don't know where the iPad will go, but just to start I see it at the university - holding my lecture notes, having all the texts I have assigned, taking notes for future lecture topics, easy access to email and the web, communicating with students in the on-line portion of my course, and many other things not yet developed or imagined.
I started with an Apple //e in the early 1980's and have always found Apple products adjust to my needs. The first thing I used the //e for was to use BASIC to design a list of locker numbers.