The OpenOffice Project has released OpenOffice 2.4.1, an open source office suite for Linux, Solaris, and Windows that saves all its files as zipped XML. 2.4.1 is a bug fix release.
I deleted Microsoft Office from my MacBook a couple of weeks ago, because of severe bugs (startup took forever). I haven't had any trouble living without it, but then I'm no longer a fulltime writer. For now I'm just using Google Docs as my replacement. Openoffice is still too ugly to tolerate.