I have been recommending to others for some time that they consider NeoOffice as a free/open-source replacement for Micro$oft Office. NeoOffice is a port of OpenOffice, which needed the Unix X11 interface wrapper to run on OS X. (Translation: it ran slow and didn't look Mac-like and was complicated to run since it relied on the Unix under-pinnings of your Mac.)
This is changing with version 3 of OpenOffice... they are porting it to Aqua which means it runs like and looks like other Mac apps. Here is a first look at the OpenOffice.org 3.0 Beta just released this week and things look promising. When it goes to full release, I expect I will be deploying it and recommending it.
On a side note, Recently in the comments, a NeoOffice aficionado mentioned that the NeoOffice team may continue development past OO 3.0. This concerns me. I know alot of work has gone into the excellent NeoOffice but if it gets deprecated, it gets deprecated. I recently sent money to NeoOffice project and don't regret it for a second, even if its need is shortlived. I will be interested to see a public statement from the NeoOffice team on intentions when the time comes. It is too soon to expect that from them at this time. Much will depend on the shape and sustainability of the final OO 3.0 release.
The big news is that this is all great for the state of open source productivity apps on the Mac.