I remember all the articles about how mice would never catch on, and what a terrible idea it was.
"You have to take a hand off the keyboard", they said.
"You then have to look for a menu, find the command you need, and then press the button", they said.
"You then have to bring your hand back to the keyboard", they said.
"It's much easier to remember a two or three key command for these things so you don't waste time and effort moving your hand, and eyes", they said.
They were right. The mouse never caught on.
We're getting the same thing now with those opposed to multiTouch.
Greasy hands on the keyboard or mouse, same thing as on the monitor, except that the monitor is vastly easier to clean. And, not everyone has dirty hands most of the time.
Much easier making gestures on a screen than using a mouse or keyboard.
People will get used to it, and wonder how we did without, just like the mouse (and trackball, which I prefer).
I'm totally thinking about it like this.