Security:
ClamAV & clamXav — Industry standard anti-virus applications. The first link is for Windows and Linux, the second for Mac OS X
KeePassX — Stop using your pet’s name as a password, or placing sticky notes on your monitor…
dban — When you sell, give away or otherwise dispose of your old computer, make sure you erase data from the hard disk
prey recovery — Increase your chances of getting your stolen laptop back
Office & Productivity:
Abiword — Word processing, plain and simple, but still very powerful
OpenOffice — Comprehensive and complete office productivity. The latest release is much faster, too!
calibre — Paper is still better, but if you must read books on your computer, this is the best e-book management tool around.
LyX — A different way to produce professional documents
Development:
Netbeans IDE — Sophisticated Web application development
Kompozer — WYSIWYG website creation, similar to Dreamweaver™
Multimedia:
Mplayer — Not so straightforward, but a very powerful and versatile movie player
vlc — Plays almost any audio or video file, and can stream to your local network
avidemux — Simple movie editor and transcoder
audacity — Deceptively simple audio recorder and editor
ffmpeg — Very powerful toolkit for transcoding and media extraction
Internet & network:
Firefox — Arguably the most popular, secure and customizable free web browser. Firefox is a must for any serious web development
Filezilla — Quickly transfer files over your LAN, or to and from remote servers
Graphics:
GIMP — Slightly eccentric interface, this is the best free graphics editor available. Many plugins available.
scribus — Professional page layout system.
