- KeePassX. A free password manager that runs on Mac OSX and Windows.
- Keka (free software)
Allows you to create zip files that are split in to multiple volumes (e.g. multiple files 50MB each).
File sharing / Downloaging (free softare)
- FileZilla (free software)
Filemanager with more abilities than the MAC OS finder:
- muCommander (free software)
After you upgrade to Mac osx Lion, you might stop being able to connect to some samba shared folders and network drives. This file manager can still connect and you can access your shared/network files.
Media players (video, audio players)
- NicePlayer. Simple media player with ability to open multiple video windows:
- VCL player. Media player that plays most of the video formats
Amazing media player and video library
Xbox media center - XBMC (free software)
- Finds automatically the movie art work and covers
- finds automatically the subtitles
- organizes automatically movies by artist and gender
OpenOffice (free software)
Better email client than Mac OS mail:
ThunderBird (free software)
Picasa (free software)
(Finds duplicate photos, uploads to google photo gallery)
Sip Client (VOIP soft phone)
ZOIPcommunicator (free software)
Adium (msn and other networks client - free software)
All2mp3 (free software)
Converts many audio formats to mp3, for example flac to mp3
You cannot always do such conversions via itunes.