As I mentioned in our review of the first iPad last year, this is a device that augments your existing setup - it replaces nothing. You'll still need a computer of some sort and you'll still need a phone, you just get to have another device that's more convenient than both of those occasionally.
Anand once again nails it. This is exactly the point of the iPad: it’s better (read: more convenient) than a laptop or a smartphone at certain things that people actually do every day. For many people this is a legitimate reason to buy one, and it’s easy to see why. Now, could it replace any of those other devices? I honestly don’t think so, at least not yet, and that’s the reason I didn’t buy the first generation iPad.
However, it is quickly becoming so much more convenient at those tasks that I can easily see it as the first go-to device for many, many people in the not-so-distant future. And it’s only going to get better. In my case, the platform is mature enough that I can finally wander into it with confidence.