John Gruber has written a nice substantial post asking a question I've often asked myself here: who really needs an Apple tablet? He says that he's heard the tablet is real, and that it's still a well-kept secret -- all of the rumors we've heard so far are still just rumors. But the real question behind the device is what it's for. Like Gruber, I don't believe it's just a tablet PC running OS X -- the MacBook is already portable and powerful enough, in all of its incarnations, to serve that purpose, even if it doesn't have a touchscreen or a smaller footprint.
I agree with Gruber that if Apple is releasing a "tablet" next month, it'll be more towards the iPhone side of things: a specific OS and UI designed for doing all of the little computing things you do with a portable computer. You don't necessarily sit down to edit video while curled up in bed or sitting on the train, just like you don't edit video (though you can) with your iPhone.
But you do read, browse the web, check and write email, watch video, maybe play some games. The phrase Gruber eventually attaches to all of this is "personal portable general computing," and I think he's dead on. While the iPhone is a suitable replacement for most of this, there's an upper limit on it as a smartphone. But the tablet, with a specialized UI, OS, and even App Store-style apps, can fit that category perfectly.
Very interesting writeup. Gruber says early in the post that the iPhone was a complete secret before it released, and that's not quite true -- we all knew there was going to be an Apple phone eventually, even if we didn't know specifics (and yes, some of the guesses were silly). And I think likewise, we all have a good idea already of what an Apple tablet will be like, even if the specifics of the device will end up surprising us after all.