I find that variety helps: Use one thing for a while, then use something else. Right now I love my little notebook computer with a touch screen. That, and a good trackpad, allow me to keep my hands in a neutral position, which is like a loosely closed fist with the index fingers pointing outward.

My other issue is eyestrain. I can type text without looking at the screen, so I tend to prefer text based interfaces. And keyboard shortcuts are a way to rest from overuse of pointing devices. (i.e., overuse of our bodies)

Remember the urban legend about the QWERTY keyboard, that it was designed to slow us down in order to distract us from how slow typewriters were? Sometimes I wonder if the modern GUI has turned into something like that: Simple tasks require us to control the computer's sequence of operations through extensive manual and ocular labor, rather than us just telling it what we want it to do.

Just a weird thought, offered for amusement.