Abiword's stated goal is to be a fully-functional WYSIWIG word editor. It is not quite there yet (most notably, tables are lacking) but otherwise it works very well. It can also imput/export rtf and PalmDoc files, both of which can be quite useful.
To run Abiword, type /lusr/gnome/bin/abiword. This only works if you are on a Linux machine (AbiWord does not support SunOS yet).
Abiword is licenced under the GPL; its source code is available from http://www.abisource.com/developer.phtml.