Karl-Peter Gottschalk talks about ergonomic keyboards. I use the Microsoft Natural Keyboard (as in the original, before the Pro that Karl-Peter uses) that's been around the house quite a while. Long enough that it's implausibly dusty and, well, gunky from having some of a can of soda spilled on it a year-plus ago.
With the upcoming regime change I've veiledly mentioned once, I've been considering getting a new keyboard--a Happy Hacker Lite 2, like Ink uses and likes. I'm worried it'll take me a while to adjust from this split keyboard, though, and if it'll increase my wrist pain (which right now is roughly nil).
I was going to comment here that the SmartBoard is so much more expensive, but then I realized I was still looking at the Australian distributor site. Datadesk's published prices are comparable.