[daltore]

As far as graphics programs, I second Gimp and Inkscape. I also like Blender as much as I don't know how to use it. Also:

-Hugin - Panorama creator
-Xara Xtreme - Vector graphics program in case Inkscape doesn't work on your computer

Other open-source programs I love:

-Audacity - General purpose audio editor with thousands of available plugins
-Rosegarden - MIDI composition program, similar scale to Finale
-Avidemux - Basic-function non-linear video editor
-VLC - Media player and converter (through Transcode)
-Pidgin - Multi-service IM client. Supports Jabber through MSN.
-Rhythmbox - Audio manager similar to iTunes, but free. Maybe only Linux, not sure
-Firefox and Thunderbird - Web browser and e-mail client. Obviously, just mentioning.
-Piklab - Clone of MPLab. Unfortunately, no clone of C18 yet.
-pictools - Java version of IFI Loader, works on Linux.
-Ubuntu Linux - Free operating system, some of the best compatibility of all the Linux branches.

Web-apps:
-http://compiler.amadis.sytes.net/compiler32_form.php - Fully functional public Windows 32-bit C[++] compiler.

I love open-source, so if you want some more lists, send me a message.