As a Mac and iPhone software tester, I'm itching to get my hands on an iPad as soon as possible. I told one of our engineers today that I think it's essential for testers to literally get their hands on these devices. I did some iPhone testing before I owned one, and did a decent job of finding bugs on borrowed devices and the simulator. But once I got an iPhone and began to use it day-to-day, I discovered all sorts of new user scenarios. Airplanes, reading in bed, Seattle weather, ... I expect the iPad will not be just a giant iPhone, but have a whole new set of interactions. I look forward to the discoveries. And who can turn down a shiny new toy?
Some other people have written much more eloquently on why it's not just a giant iPhone:
http://speirs.org/blog/2010/1/29/future-shock.html
http://www.mcubedsw.com/blog/index.php/site/thoughts_on_the_ipad/
http://heta.metalbat.com/?p=1998