This is becoming a controversial issue in our schools. Most schools have rules against cellphone use in the classroom, but when a phone also becomes a PC, the rules are changing. Our local school system just implemented a policy by which students with smartphones will be allowed to use them in class (presumably for web access, as they would a laptop or other conventional computer), subject to teacher approval. Obviously, with the additional capability of texting, etc., using the device to cheat will be even more of a concern, not to mention the usual distractions of such devices in the teenage (and adult!) world. Lots of opinions pro and con flying back and forth.
Real work: PC; doodling and making presentations: tablet. I have a Mac person in my household who is creative and likes to work fast. That person has fallen in love with the iPad and uses it to communicate, browse and even word process. But when it comes to real work that yields an income the person reverts back to the MacPro; the programs are just overwhelmingly more useful on the "PC" than on a tablet. But for cool interfacing using touch technology no other computer interface comes close to the intrinsic CHI experience of swipe, pinch and tap.
In terms of computing power, I think a tablet can be considered to be the same as a PC (just as netbooks are low performance PCs); although they are slower and have less memory, todays tablets are still much more powerful the machines of which everyone agreed they were high power PCs 10 years ago.
However, in my opinion, there is one main difference in software that distinguishes tablets such as the iPad from what it takes to be a real PC. The key is in the definition:
'A personal computer (PC) is any general-purpose computer'
Although an iPad is a great toy (yes, I like angry birds) it can hardly be considered as a general-purpose computer as it is dependent of the PC (and/ore network) for many essential tasks. I have to admit I am not very familiar with what the iPad can do, but for me the most striking example is that it is not possible (without assistance of a PC) to use the tablet in order to develop, debug, test and deploy applications that run on the same tablet.
This single limitation is in my opinion sufficient to claim that (such) a tablet is NOT suitable to be a general purpose computing device but it is only a specialized media consumption device that needs to rely on real PCs in order to be useable...
However, where it would get more confusing is if the same hardware would be provided with both an operating system turning it in a media consumption tablet (iOS, android, ...) and an operating system that gives it the general-purpose power of a real computer (windows, non locked-down linux, ...)
For me, the media tablet is good. But I still love to work on my laptop. It could be that since that is what I grew up with using all of the time in college and my personal life; it is hard to change. Now I really see why physiology is a popular field of study.
To find the answer, just look at the camera market.
We have DSLRs to point-and-shoot and in between so called bridge cameras. These are cameras and people by these depending on the usage. Desktops, laptops, tablets, Ipods etc all can perform certain computing/media tasks and people buy the one based on their needs. At one extreme desktop can perform heavy duty work but no mobility and at the other end of the spectrum you have ipods/tablets which cannot perform heavy-duty computing but come with extreme mobility.
I find the entire question to be silly. A number of years ago, laptops weren't useful enough to be considered for most work. Now, it's what most people are buying for their home and work computer. And then netbooks appeared. Even though people consider them to be computers, from my own experience, I find they can't run much software, and a lot of what they do run, runs poorly. So, are they computers?
Obviously, iPads, iPod Touches, and iPhones are computers. Are they computers that do the full range of work that most others do these days? Well, not yet. But at least for the tablet, they will.
I agree with you. For gaming or graphics oriented applications, I would prefer desktop over Tabs. But again if someone needs to, for example, connect with the eetimes folks while travelling, then the Tabs would be pretty handy :). I would rather call the Tabs as PCs as they are truely "personal".