I want to also mention that there are a few apps for which there is no usable Desktop alternative. In particular the Notes Plus app has nothing remotely as usable for taking notes on any Desktop platform. The thing is just incredibly smooth and transparent, it beats paper hands down. Also, Sorted is pretty sweet for managing projects. Although there are Desktop apps that will do the same thing, Sorted just makes it simple and painless.
I believe that the whole "it's just a consumption device" thing is primarily a FUD against tablets. The touch interface allows some applications to be much easier and more productive once you've learned the interface. In particular, the entire Adobe suite could work on an iPad MUCH better than any Desktop. Just because of the touch interface.
Machines have less problems. I'd like to be a machine. -- Andy Warhol