AbiWord 2.4.6 is a multi-platform Open Source word processor. I recall using it for a few months on a notebook running Microsoft Windows several years ago. I tried out an early version (1.0 beta release I believe) of OpenOffice.org and have not revisited AbiWord since then.

It's interesting that AbiWord is available for Windows and Mac OS X (as well as Linux) while the OpenOffice.org project still can't figure out how to build a native Mac OS X version yet (even though the NeoOffice Project has a solution for them ready-to-go).