Why would anyone buy an iPad

I've been wondering over the last few months why anyone would buy an Apple iPad. They seem to be fairly limited in what they can do. Wouldn't you be better off with just a smart phone or a netbook? It seems like iPad's are trying to fill a niche that isn't there.

But still people buy them. Are they using them as e-book readers, or running iPhone apps for people with poor eyesight. They just seem to bulky for what little they can do. I have to assume that I am  wrong since so many people use them, but yet I still struggle to see the value. Personally, I would even be hesitant to buy a tablet computer, when I could just go with a laptop instead. Maybe I'm just not the "target market," and that's why I don't understand.