I was skeptical about the iPad after I got one... I almost sent it back in the first week, because my thoughts were 'is that all?'.
Over a period of time I've found myself using it more and more. I've hardly used my laptop in the last year, and I've used the apps on my phone a lot less.
It's absolutely ideal for music/books/audio consumption around the house. It's a good lightweight way to get online while travelling - the weight is a LOT less than a laptop, and most of the time I don't miss any laptop functionality. When travelling, the battery life is it's killer feature.
I'm also seeing it as a great tool for music - recording, displaying printed music, as a tuner, a drum machine. In the music world a lot of companies are using it as 'virtual hardware' to run their products. The advantage over a (proper) computer is that the single screen interface removes distractions and makes it a more focussed tool.