I have an ipod Touch, iPhone and an iPad.
The iPad is not a giant iPod Touch. For one thing, it has 3G (or mine has), and higher res, its faster, it has a better screen, oh yes, BIGGER SCREEN.
That screen really makes all the difference. If you want one and can afford to, just get one.
Yet, the large memory versions cost the same as a half decent PC - which is just insane.
Apple really have people eating out of the palm of their hands, their marketing is so powerful that people don't even consider the better products on the market that generally are cheaper.
I suppose the above isn't true for the tablet market yet because it's such a new market as there's not that much choice out there yet.