Re: The trouble with 'touch' on the desktop...
I'm not sure that's a real problem for the majority of people, although it's become a common argument against touch-PCs. Touch isn't mainstream in the consumer world but touch-screens are used by some people all day in specific jobs - mostly factory-based I'd guess.
As a student I had a job as a checkout-dolly in Tesco. You spend 8 hours sitting on a chair sticking your arms out in front of you to pick up items and move them over the scanner, and interacting with a touch-screen checkout. Arguably, having to pick things up is even worse than having to stick your arms out to tap a screen, but people don't have special harnesses or whatever and you see people in their 50s who do this day in day out.
So I don't think the automatic "it's bad for you" response can be taken as gospel, any more than a chair manufacturer telling you that standing up all day is bad for you!