Nice list!
I can second
Audacity and
VLC. Both excellent, free and opensourced multiplatform softwares.
Foobar2000 is also excellent at converting file formats (I'm a
FLAC guy myself unless I need to burn a CD or load an mp3 player).
I think someone on these forums might have mentioned
Audiograbber as well, a great solution for slicing and dicing (automatic silence detection with threshhold, etc.) large files into seperate songs... I've used it quite a bit lately to convert ripped vinyl into individual song files.
Red Kawa has some free, beta versions of their Media Center software that is intended to stream photos, video and music over a LAN to a connected game console such as the Nintendo Wii or Playstation 3.
Slimserver is free, multiplatform music streaming software that I have used reliably myself for years. Excellent and while you are there you should look at their music headunits too:
http://www.slimdevices.comRecently I replaced
Winamp as my default music playback software with the excellent
XMPlay, at least on my windoze machines.
SimpleMP3 is an excellent CD ripper/converter software that I've used for years too. Don't despair if the link comes up bad... for some reason he insists on hosting on a free account at geocities.com which has very limited bandwidth. Usually when a new version comes out his website gets temporarily swamped. Google for updated mirrors or keep checking back. It's worth the trouble.
In linux I love to use
K3B for CD and DVD burning. The closest thing I have found to it is the free version of
Deepburner, IMHO superior even to Nero.
My favorite place to dig for new freeware is
http://www.snapfiles.com