Heavy computer users with persistent pain who don't at least try the Advantage are doing themselves a disservice. I wrote an extensive review of the keyboard here: http://jseliger.com/2009/07/20/kinesis-advantage . The OP might also want to try the Evoluent Vertical Mouse, which is another effort at better ergonomics.

At the moment, the top-rated post pooh-poohs purely technological solutions and says the OP should exercise. I think the keyboard/mouse combo should be used in conjunction with exercise, rather than as an either/or.