iPhone/Touch: Hold in one hand, and control with the thumb on that hand. iPad: Hold in one hand, and use the other to reach across the screen for icons and app controls. Net efficency loss. Any Win or mac OS device: Move a mouse less than an inch to access any control on the screen. Apple is still stuck in that icon array mode believing that messing with it would confuse potential customers. Looks like it might, seeing who have already bought one.
Yes, Apple has been toying with tablet ideas since the Newton. Even Steve Jobs didn't believe their designs had a chance until he saw how well the iPhone and the app developers were doing, and the suggestion of simply making a big Touch that could suckle from it's mother (iPhone apps) was what moved them to a marketable device. That, the cost of technology, and the falling profits off the aging iPhone (thanks to android's growth) all fell in place to make this the year of tablet.
I've looked VERY close at several iPads. My college tech store has three on display. I've spent more than enough time playing with them, examining the specs, talking to potential and actual buyers, and sales people who sell them to know what an iPad is and what an iPad isn't:
It's a Mac netbook. They swapped out mac OSX and replaced it with the less capable iPhone OS. They took off the keyboard so you could pay them extra for it later. They eliminated any printer driver support in what I'll guess is an effort to be "greener" and save trees. They eliminated any USB ports, SD slots, VGA outputs, so they could charge extra for them later. They sealed the case so owners can't upgrade their own memory, and eliminated native network sharing access to force you to use iTunes and (reluctantly) 3rd party apps for all your content. Then they doubled the price (compared to a netbook). Lastly, they inflicted it with that Apple-only dock connector that forces you and every 3rd party device maker to pay them a licensing fee just to make/sell a compatible device that uses it.
Did I miss anything? Oh yea: Since they're using nothing larger than the motherboard from a cell phone in it (see ifixit's tear-down) they could fit a huge battery in there. When it wears out you won't be able to replace it, but they'll gladly collect another $100 from you to do it. So what is an iPad? An amazing profit maker for Apple, thanks to the suckers who buy it simply because Apple made it. If HP or Dell or ASUS or even Microsoft had done exactly the same thing you kids would be laughing and pointing and trashing it to no end.