Multimedia

VLC Media Player

http://www.videolan.org/

Great media player supporting most audio and video formats.

CDex

http://cdexos.sourceforge.net/

Convert CDs to MP3, Ogg, etc..

i-FunBox

http://i-funbox.com/

Backup musics and videos from an iPod / iPhone / iPad.

WinAmp

http://www.winamp.com/

Famous audio player.

dBpowerAMP Music Converter

http://www.dbpoweramp.com/dmc.htm

Converts audio files from one format to another.

The GodFather

http://www.jtclipper.eu/thegodfather/

Edit music files IDv3 tags. Retrieves information from the Internet.

Audacity

http://audacity.sourceforge.net/

Edit audio files.

HandBrake

http://handbrake.fr/

Converts video from one format to another.

Free FLV converter

http://www.koyotesoft.com/

Download and convert Flash video (YouTube, DailyMotion, etc..) To other formats.

Codecs

FFDShow

http://www.free-codecs.com/download/FFDShow.htm

Decodes the MPEG-4 files (DivX, XviD, etc...).

Haali Media Splitter

http://haali.su/mkv/

Decodes the MKV files.

QuickTime Alternative

http://www.free-codecs.com/download/QuickTime_Alternative.htm

Decodes the QuickTime (MOV) files.

Real Alternative

http://www.free-codecs.com/download/Real_Alternative.htm

Decodes the RealMedia files.

DirectVobSub

http://www.free-codecs.com/download/DirectVobSub.htm

Insert subtitles (srt, ass, etc... files) over videos.