The original Microsoft Natural was okay, but a bit unreliable. Then they came out with the Natural 31337, which is a bitch and a half to use for anything other than websurfing (hint: websurfing only uses the mouse). Now they've got the Pro, which has now integrated the hardware with the browser as well. :P

I've found that the best keyboard is this little notebook-keyboard-sized SunRace I picked up in Hong Kong for about US$18. It's got the layout of a notebook, but its key action is much better than even a desktop keyboard - in fact, it feels like a desktop with a much shorter, yet firmer, key travel. Now normal keyboards feel like I'm moving my fingers miles on each keystroke in comparison - this one is definitely easier on my wrists, due to less finger travel, and I can also type faster to boot. It's also got a few fringe benefits... for example, due to the seemingly-unintuitive placement of the Fn key (for accessing the numeric keypad), you have to use your left thumb to hit Ctrl - which is a hell of a lot better than having to use your pinky, ergonomically.

Unfortunately, I can't find a URL or distributor within the United States. They're very easy to find in Hong Kong. I actually brought back three - one for home, one for office, and one to sell to Dr. Leung, who wants one because of the Chinese symbols on it (his son is interested in learning Chinese typing).