I think touch screens are great. I think tablets are great. I think smartphones are great. The touch interface and its accompanying experience has been expanding rapidly for a few years now and it has achieved the favored status of becoming something of a fad. People are interested in touch screens. The technology is desirable.
While I am in favor of this development, I personally wanted to note that while touch screens are good, they are only good to a certain point, after which they become the opposite of good. Generally speaking, I am in favor of changes and evolutions to interface which represent steps forward in efficiency and ease of use. Touch screens give us that in many areas. Where they do not give us a step forward in efficiency or ease of use is in the area of data entry.
When it comes to replacing the mouse, I can see touch as evolving into a possibly superior alternative. I'm not saying it will. I am just saying it could. There are certainly applications where tapping a screen with your finger will accomplish what you need faster than dragging a pointer to the spot might. Not much faster, but faster nonetheless (and possibly more intuitive).
However, when it comes to replacing the keyboard, the touch screen has a long long way to go if it could at all. The keyboard, to me, is almost the pinnacle of efficiency and ease of use. Quite likely I am just ignorant, but I am not currently aware of any other means of data entry which can achieve such dizzying highs of speed and accuracy as the keyboard (whether QWERTY or DVS or whatever else is to be ignored at this moment). When I look at tablet computers I am excited for the future, I truly am. They have one enormous outstanding flaw, though: they lack a keyboard or any really compelling means by which you might attach one.
When I hear about touch screen keyboards being designed so well that they allow for "amazing" speeds like 30WPM, I can't help but grimace. That's not enough. My own personal 72WPM frowns at the concept of taking so giant a leap backward. And that's not even taking into consideration the fact that the fastest typists in the world can lay down sustained numbers like 150WPM with recorded highs like 212WPM.
Perhaps the keyboard is destined to be replaced some day. Perhaps the touch screen will figure out a way to cross that bridge. As of right now, though, there really is no replacement for the keyboard.