I find that it really does have business uses. In our IT department we take one with us as we do our rounds and have instant access to our personal email, web and internal system documentation and knowledgebases, and even our workstations' desktops if necessary. We can also check on the service desk queue to see if there are any service calls in our current location if we're out and about to more efficiently deal with issues.
On the domestic front there's no end to the possibilities. I have apps to control my home theatre system, stream media to the iPad whilst relaxing in bed or on the couch, read books with interactive content, games of course, and... you name it. Also, some apps are actually more fun and cool on the iPad than their desktop versions, Google Earth being a good example. Using one's fingers to manipulate the planet is as close to playing god as most people are going to get.
All of this in a package which is far more convenient, lightweight, and with greater battery life than a typical laptop; not to mention the fact that most of the apps are vastly cheaper than desktop versions, and sometimes free.
Oh, and lest we forget, these are very rugged devices. I've tested mine in an environment that's tougher than that used for stressing military hardware: kids. And not a scratch. Give a kid a netbook and I guarantee the hinges will be utterly destroyed in minutes.