I bought a 16gb iPad the week after they came out. I didn't really have a need for it, I just wanted to see if it was interesting. I had a very simliar experience as the author.
My wife has little but distain for my gadget obsession, but within minutes she wanted one for herself. Our three-year-old adores it. I put some educational games and cartoons on it, and she can get to it all on her own. Literally every person I've shown it to has wanted one.
Want one is the keyword. I've played with my coworkers iPad quite a bit and can see how it could fit into my life. But at the same time its not a need - not in the way I need my smartphone. Its a big shiny toy that I want but only when its convient.
Still, Apple's good at making stuff people both want _and_ use. I didn't expect my mother to start using Mail and Safari on her iPhone. I only bought it for her so she could have a phone+ipod, and because she never figured out how to use T9.
I've been using it, and I think the reason people like it is because of its obvious portability and accessibility. Internet is nice and all, but it is being able to watch netflix at the gym, kindle during the commute and have all my files through dropbox that really cut it for me.
The iPad does to the internet what the iPod did to music.
I don't really need that done to the internet for me, but I can see how millions of people would really like it.