I've been keeping an eye on OpenOffice, the open source office suite for some time. The reasons that I haven't switched to it full time are that compatibility with complex Microsoft documents was never 100% reliable in the past, and that the Mac version required X Windows, which was always a pain.
I'm revisiting it now, as I am going to give Linux a serious crack as my main O/S at work soon, and will therefore be using OpenOffice as my default office suite. It would therefore make sense to use OpenOffice on my Mac at home as well. I'm pleased to say that the compatibility with MS documents is supposed to be way better in OpenOffice 2.0 (which is what I'll run on my Linux machine at work), and also, since June, NeoOffice has been available, which is a port of OpenOffice 1.1.4 for Mac OS X that runs natively without X. I'll be installing it shortly.......