Define personal computer.
A computer to me is a device that allows you to compute extensive calculations and increase work efficiency for tasks.
My computer is used mainly for typing and doing analysis alongside and running program's like solid works. Both require extensive screen space, plenty of fine control along with space to fit tasks from basic formatting to providing options for much more complex operations, and the engineering stuff requires a lot of power (yes I know the iPad will get more and more powerful but so do programs get more and more demanding)
All these tasks are much better suited to a large desktop (my 27" iMac has aided my final year project so much by being able to have word, excel and a web page open all alongside each other)
Performing any of these tasks on an iPad would be a nightmare. iPads are (as apple has always said) media consumption devices. At this they are perfect. I know because I'm typing on one now. The fact that I can pick it up and take it anywhere no problem at all on a screen big enough to consume most info that I'm likely to need on the go comfortably means its the perfect portable companion. I'm glad it destroyed the netbook, because I've never used a netbook that wasn't just a compromised crap laptop. Apple instead of just trying to. Rehash a laptop took the idea of how to make a small portable media consumption device and designed it frothe ground up to be ideal for that task.
The iPad is amazing at what it does. But it does not do what a computer is properly intended to do and to me it will never replace a proper computer. I think theyre brilliant, but if I was advising someone to get just one device I'd say get a proper computer, if they already have a desktop and need something more portable, an iPad is the perfect companion over a more expensive laptop unless the extra power is TRUELY needed.