I will draw your attention to Apple's own slides, where they place the iPad between the iPhone (and smartphones in general) and a MacBook (and personal computer

I will draw your attention to Apple's own slides, where they place the iPad between the iPhone (and smartphones in general) and a MacBook (and personal computers in general). They are undoubtedly interested in selling all three for some time to come. Will it supplant personal computers for some people? Sure. It just means that personal computers will have to shift to doing what they do best even better. It might drain a lot of life from the netbook market, but that's about it.