Craig Hockenberry writes about Multi-touch on the desktop:
"If you’re one of the people who think that a multi-touch monitor is a good idea, try this little experiment: touch the top and bottom of your display repeatedly for five minutes. Unless you’re able to beat the governor of California in an arm wrestling match, you’ll give up well before that time limit."
As much as I want mutlti-touch monitors, I think he's right. A little physical gesture pad would be cool though :)