I was recently checking out some of the new HP home computers with touch and my first thought was cool. After a minute it changed to cool, but pointless. If you're using a desktop it's awkward at best to leave the keyboard and mouse to touch the screen.
I haven't seen these, but it sounds as though touch has simply been added to an existing interface (probably Windows). Ideally the interface should be designed with touch in mind from the start, then you don't need a mouse and the only reason for a keyboard is for extended text input. Ideally you should have either an on-screen touch keyboard or maybe some other virtual keyboard (like this
?). Hence wouldn't leave the keyboard and mouse to touch the screen
since you'd be using the screen all the time and might occaionally leave the screen to use the keyboard
Of course, I'm reminded of the Apple Newton as a technology which was ahead of its time and failed to catch on, largely because people couldn't get past the learning curve, that is, when the machine learned your handwriting, and fell back to using on screen keyboards or gesture systems. Hence, the product didn't sell well and it took another 10 years before PDAs without hard keyboards started catching on.
I think large multi-touch screens won't catch on quickly if they are simply used with existing Windows tools instead of specific multi-touch applications. As mentioned, it all depends on what products appear and how useful they are. Presentations and graphic design tools are possible as is, of course, gaming, but anything with large amounts of text-based input will probably not benefit much.