FLAC - Free Lossless Audio Codec. Use this format to compress sound files which you are going to edit. As I recall my experience, this only reduces the file size to about half of uncompressed PCM, but repeated loads, edits and saves of lossy formats can degrade your file.
Ogg Vorbis is a royalty free lossy audio codec. If you don't want to worry about mp3 royalties, use this. In my experience, this format has great compression without noticable artifacts. I would say it may be somewhat useable for editing. I have had great results with really small bitrates-32 kbits/sec and less. However, speex was made for low bitrate speech, so it is worth looking into as well.
toolame is a free mp2 encoder. Apparently no one is asking for mp2 royalties? Doesn't seem to be much here but a source tarball, but I know at least Debian has them in their packaging system. I use it for encoding to my portable mp3 player. There is a spinoff called TwoLAME. It seems more lively, but still only source tarball is available.
One could technically use lame to encode mp3s, but legally it is only allowed for educational / research use or somesuch. Fraunhofer is really agressive about enforcing it's patents on mp3s.
EasyTag - this appears to be a good mp3 tag editor. Haven't had a chance to try it out yet.
Ogg Theora is a royalty free video codec donated by a company called ON2. It originated from their VP3 codec. Ogg also supposedly has another video code coming out called Tarkin, I think. I swear I rarely ever see anything working with them, so I have to wonder if they are just fantasies... I did see a video encoded with Theora on the Ubuntu CD, but that is about it. I have really tried hard to encode videos with Theora, but I never seem to make it to the point of actually ecoding a video. Supposedly MPlayer will do it, but I haven't been successful.
official blender model repository
Art of Illusion - 3d Modelling and rendering. I have used this quite a bit.
Povray - A very old raytracer.
Some tutorials at the official site
gimp-savvy.com Site contains a book for learning how to use the GNU Image Manipulation Program--"Grokking the GIMP" -- Also has an index of free images from government sources.
gimp-tutorials.com gimpguru.org/Tutorials gimp-tutorials.net
Steampunk tutorial -- Steampunk is sort of an offshoot of Sci-Fi where basically the US Wild West goes high tech in certian ways.
This Nicu guy has some great stuff, like some kick-ass rpg clip art