The finest keyboard you can buy. It's designed for the Mac but is USB.
http://matias.ca/tactilepro/index.phpIt uses the old-style mechanical keyswitches, which were standard until the mushy membrane tech came along. That tech is why keyboards are $30 now, but it's also why they suck rocks. Anyone who ever used, say, an IBM PC XT keyboard will remember the mechanical kinds and how good they were to type on.