Alot of the criticism of Apple's iPad stems from the computing features is lacks. It seems many people want it to be a computer, and it's not. Leo Laporte has it right in describing it as a content consumption device, instead of a content production device.
I'm not going to join the fray in Apple bashing at this point. I also have no intention of picking one up. The platform has me thinking, though.
What if, instead of using it as a computer, or instead of using it like a computer, or instead of using it as a display/network interface, you used it as secondary mouse?
I'd be interested in a Tablet like device that sits next to my keyboard, mouse, and computer.
Imagine you are editing audio files. You have your application running on your real computer. You have virtual sliders, nobs, splicers, and other things that today you manipulate with a mouse. Now, what if the application still ran on your real computer, but on your nobs and sliders appeared on your Tablet? Now, you can use your fingers to control things on the real computer, and you don't clutter up your big screen interface with those controls.
This is different from the current iPad use case because the Tablet here is a "dumb" device. All it does is display the controls and accept your input.
Imagine you are playing the latest incarnation of a World of Warcraft or a first person shooter. Obviously, the portable tablet wouldn't have the power to run such applications in all the full color, high graphics wonder. But if it's another input device, hooked into your real computer, it becomes more powerful. Instead of using key combos, or navigating complex menus in the heat of battle, you look over at your Tablet which displays your favorite buttons or macros. Perhaps they change depending on what is happening on your other monitor at that point in the game.
We already see some of this capability in Optimus keyboard. It features OLED keys. Basically, the keyboard physically looks like most other keyboards, but the letters on each key can change. You can choose a different typing layout, or do your own short cuts and macros. You can replace the letters with images electronically.
A Tablet device that works as a input device for your computer, separate from your main computer screen, and that changes its own appearance could be an awesome tool.