Free software that might be of interest

Office package (Cross platform)
http://www.openoffice.org/

CAD software (Cross platform)
http://sourceforge.net/apps/mediawiki/free-cad/index.php?title=Main_Page

3D modeling (Cross platform)
http://www.blender.org/

DVD Authoring (Windows)
http://www.dvdflick.net/

(Will update as I remember other software worth checking)