Aqualung is an advanced music player originally targeted at the GNU/Linux operating system, and also running on FreeBSD, OpenBSD, and Microsoft Windows. It plays audio CDs, Internet radio streams, and podcasts as well as sound files in just about any audio format, and has the feature of inserting no gaps between adjacent tracks.
Goggles Music Manager is a music collection manager and player that automatically categorizes Ogg Vorbis, FLAC, MP3, MP4, ASF, and Musepack files based on genre, artist, album, and song. It supports gapless playback, features easy tag editing, and allows scrobbling tracks to last-fm.
Zina is a graphical interface to your MP3 collection, a personal jukebox, a Podcaster, and an MP3 streamer. It includes an optional Flash player, a tag editor, and can search the Web for album art and song lyrics. It can run alone, be embedded into an existing Web site, or be used as a module in Drupal, Joomla, and Wordpress.