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)