I've started seriously investigating OpenOffice.org, an open-source office suite which is a popular alternative to Microsoft Office, especially among users of the Linux operating system, but recently gaining a lot of interest amonst Windows users as well.
So far I've only been looking at Writer, the equivalent of MS Word, but OpenOffice includes the other standard office suite components as well: spreadsheets, presentations, drawing, and web publishing. It does not include a database, but it does include the ability to interact with a database such as MySQL.
I'll be writing up my research on this page.
Now available: Taming OpenOffice.org Writer, for people who are new to OOo but are intermediate or advanced users of other word processing programs such as Microsoft Word. More information is here.
Sources of information
The OpenOffice.org website is here: http://www.openoffice.org/
Travis Bauer's site http://www.ooextras.org/ has all sorts of goodies: templates, macros, and so on.
The OOo documentation project is at http://www.ooodocs.org/
Book (now available): OpenOffice.org 1.0 Resource Kit by Solveig Haugland and Floyd Jones, paperback, 1040 pages + CD-ROM, Prentice Hall, ISBN 0131407457; Order from Amazon.com.