Today, there are two distinct breeds of computers: desktops and notebooks. The first of these to receive multi-touch across the board will be notebooks.
Why is this? Because it makes more sense to be able to condense the machine to the point where a keyboard and trackpad become integrated into the screen, necessary only when a user requires it. This is already seen in the iPhone, and as other portable devices adopt this process, the "notebook" will leave its form factor, and most likely be replaced by the tablet.
The wrong way of doing this is how Microsoft is pursuing with Windows 7. Using the current form notebook mixed with multitouch just looks painful to use, and does not offer the ease of use as in a tablet format. Watch the video
here.
But sooner than later, Apple will release a tablet that uses multitouch technology, and other PC vendors will attempt to do the same. And over time, you'll notice that more tablets will be sold than notebooks. Thus the demise of the notebook era will have begun.
On the other hand, how will multitouch be integrated into desktops? When I picture the current iMac in my head, holding my hands up and moving stuff around simply does not seem comfortable, especially after a few hours of floating my hands above my tabletop. To tell you the truth, the closest attempt we've seen is the Microsoft
Surface.
While I don't think a coffee table that doubles as a computer is exactly the right form factor, I think we'll someday see the iMac change direction from vertical to horizontal. Maybe it'll be just slightly diagonal, sitting at a 45° angle, facing the user's eyes so that it doesn't cause neck strain. In addition, the users hands won't have to be held up like the design of the past, but sit nicely on the table top, just as if they were typing on a keyboard, but instead, they're using multitouch on an iMac.
So would I like to see a multitouch iMac? Absolutely. In this form factor? Not a chance. Give it several more years and we'll defininately see it though -- first in iPhone, then briefly in notebooks, then in tablets, and finally on desktops.