There has been some discussion and rumors swirling around about Apple and a tablet PC of some sort. John Gruber discussed it, as did Paul Bucheit, and the comments on Hacker News has some insights too. For the record, here is my prediction, from the software side of view:

Apple will release some sort of tablet device, as rumored, and the primary input method will be the touchscreen. The UI will be a more advanced form of the iPhone UI, as Gruber suggests. The tablet may have similar specs to the MacBook Air. Apple will position it as a partial replacement to a full-powered MacBook/Pro, again, as Gruber suggests, targeting casual Mac users who don’t need the full power of Mac OS X.

So far, I have not said anything new.

What no one seems to have realized, yet, is that Apple will also target more heavy users of Macs - perhaps those who write a lot for a living (writers, reporters, mid-level managers who seem to do nothing but generate email after email, etc).

Apple’s current mouse and keyboard are both Bluetooth-only. I predict Apple’s tablet will allow for a more conventional Mac OS X UI, and allow regular applications to run, and allow input using the standard Mac keyboard and the Magic Mouse.

How Apple accomplishes a seamless switch between the two disparate UIs (the conventional Mac OS X UI and the tablet-touchscreen UI) will be interesting.