PC Tonic

Audacity ~ Audacity Developer Team
*****
Available for: Windows Vista/XP/2000/ME/98
Overview: A very popular and richly featured open-source audio editor.
Home | Download.com | FileHippo

Any Audio Converter ~ Any-Audio-Converter-Team
*****
Available for: Windows Vista/XP/2000/NT
Overview: As the name says, it’s an any-audio converter!
Home | Download.com

Mixxx ~ Adam Davison, Albert Soni
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Available for: Windows Vista/XP
Overview: Power packed open source DJ tool.
Home | Download.com

Switch ~ NCH Software
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Available for: Windows Vista/2003 Server/XP/2000/ME/98
Overview: Handy audio converter with support for a large number of audio formats.
Home | Download.com

AoA Audio Extractor ~ AoA Media
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Available for: Windows Vista/2003 Server/XP/2000/ME/NT/98
Overview: Software to extract audio from CDs and save it in a wide variety of formats like mp3, ogg, wav etc.
Home | Download.com

CDex ~ Albert L. Faber
*****
Available for: Windows Vista/XP/2003 Server/2000/ME/98/95
Overview: Open source and very popular CD extracting tool.
Home | Download.com

Check out a list of free media players too.