A short list of great opensource (free, as in freedom) software

Openoffice, like microsoft office but free

Firefox, the best internet browser (from the ashes of Netscape Navigator) with tons of powerful plug-ins

Thunderbird, very good email software (but you need it only if you dont use gmail)

Mwsnap, to take picture of what is shown on your monitor (this one is freeware, not real opensource!)

Vlc Mediaplayer, the best videoplayer around (can read almost everything)

The Gimp, a free alternative to photoshop (almost)

Scribus, a good desktop publishing software

Inkscape, opensource vector graphic editor

Pdf Creator, creates a virtual printer which generates pdf

on your desktop instead of printed paper [just try it!]

Filezilla, a great FTP client and a great FTP server

Scorched 3d, a very nice online multiplayer game in 3D

Freeciv, an opensource remake of Civilization

Poweroff, auto shutdown for you PC (freeware, not opensource!)

7zip, to zip/unzip files

also free to use, but not opensource

AVG antivirus, a good and free to use antivirus software

Spybot, a powerful anti spyware/adware software

and last but not least, my favourite firefox plug-ins

VideoDownloader, to download youtube video on your HD

PicLens, to browse online image gallery in 3D (incredibile, try it on your facebook photo archive)

Web Developer, useful if you know what HTML is…