OpenOffice is a worthy alternative
The final version of Open-Office.org 3, the open source competitor to Micro-soft Office, came out two weeks ago and looks better than ever.
I've been using its predecessors for years, and, broadly speaking, OO3 is the most useful, widely compatible software ever. You can run it on anything: Macs, PCs, Linux, Unix workstations. It includes six full-blown applications: the Writer word processor, Calc spreadsheet, Impress presentations program, Base database program, Math equation editor, and Draw graphics program. And it doesn't cost a penny.
The most interesting development is improved installation on the Mac. With previous versions you had to install a Unix windowing environment, X11, a non-trivial and potentially frustrating procedure that's an instant turnoff to many Macophiles. It also had a nonstandard look and feel. Now you just download and install OpenOffice and run it like any normal Mac application. If you own a Mac, it's worth trying.
File compatibility, which has played a big role in blocking wider adoption of OpenOffice, continues to improve. It can open documents from Microsoft Office 2007 for the PC, and Office 2008 for the Mac, as well as open and save documents in Open Document Format 1.2.