I love the MS 'Natural Ergonomic Keyboard 4000'. It feels a bit goofy at first, but it's really nice once you get used to it (There's this riser thing that goes on the front, so it puts your hands in a position where they fall down from the wrist instead of angling up). I work IT for a small city government, and the dispatchers in the police department -love- them. Hit up newegg (or your preferred hardware seller) and search for fa6-00010. The included mouse isn't too bad either.

Another recommendation that may sound stupid but is actually great: get a gamer mousepad...one of those gigantic ones with a nice wrist rest. I use a Razer eXactMat, and I love it. The bigger mousepad makes it much easier to get in the habit of mousing with your arm, not your wrist.