As it is, I already use my iPhone more than I use my laptop anyway: when I wake up, I check my email on my iPhone, not on my laptop. When I want to see the weather, I check it on the iPhone, not on my laptop… The list goes on.
When I use my laptop, most of the time I use it to watch video or browse the internet in bed or in the living room couch. The iPad should do all these things more comfortably than my laptop. The only thing it’s really missing for me is a webcam for videoconferencing. I’m not saying that it will replace my laptop… but it may end up being an additional toy.