After my first couple of years of working full time, my right forearm started to hurt and ache. I felt that my right hand was just doing too much work, so I started using a trackball with my left hand. I'm right handed, but it was relatively easy to train my left hand to use a trackball. This has really saved me and a few others that have tried it as well.
The other critical component is a natural keyboard. I like Microsoft's, but any split keyboard will do the job as long as you like it.
People seem to be using laptops more and more for everyday use. They are really bad for you to work on for any extended period of time. I have been working from home a bit and just couldn't take my right forearm getting sore and tired from the laptop and track pad. I don't have enough room at home to setup a second monitor, so I had to improvise a bit. This is the first day with the setup. Once I get the monitor height right, I'll find something better than a shoe box + magazines + books.