Multi touch is the first significant interface paradigm shift since the mouse and it's pretty funny to see people react with all the naysaying just like people did for the mouse (and, lest we forget, all that naysaying is one reason the original Mac was forced into a niche market.)
Whether it's directly on screen, touching from the back of the screen or using a keyboard/touch-surface combination, this newish way to interface has merit in both intuitiveness (kids and grandmas can get it) and efficiency (give me a mouse equivalent to zooming, moving, and rotating a photo as easily as with multitouch if you disagree.)
The visual interface will need to transform in order for it to be utilized better in just the same way the interface transformed after the mouse replaced the keyboard as the primary input device. Also, the form factor of a computer could very well change. I can see the iMac leaning towards a sort of light table configuration for instance.
Personally, I hope the implementations begin to include optional pressure sensitive stylus input, as well. This would be like shown in a previous Apple patent. It recognizes the signature of the side of your hand pressing against the surface and ignores it while looking for the tiny stylus "blob".
Fight it if you want. I look forward to Apple's demonstrations which will, at the very least, have more flair. At least the photos will have young people in the outdoors and stuff.
(Oh, and all these naysayers on Microsoft R&D. The Surface is real, and excellently implemented with plenty of new ideas and will be widespread in a couple years. I'm no lover of Microsoft but at least have the decency/objectivity to recognize when they come up with some great stuff!)