Sonic Visualiser is an application for viewing and analysing the contents of music audio files, containing advanced waveform and spectrogram viewers as well as editors for many sorts of audio annotations. It supports sophisticated audio selection, looping, and playback features, as well as the Vamp audio feature extraction plugin format.
Audacity is a cross-platform multitrack audio editor. It allows you to record sounds directly or to import Ogg, WAV, AIFF, AU, IRCAM, or MP3 files. It features a few simple effects, all of the editing features you should need, and unlimited undo. The audio I/O uses PortAudio, which fully supports OSS, Mac OS X CoreAudio, and Windows WMME, and can be compiled with support for ALSA and Jack.
Jaikoz is a powerful tag editor that allows you to organize, edit, and correct thousands of audio tags with ease. Jaikoz has powerful automation features. Jaikoz uses MusicBrainz and MusicIP, online databases of over 5 million songs, which can match your songs automtically based on the actual music as well as the metadata. Jaikoz uses a convenient spreadsheet view to allow you to edit information very quickly and provides many autoformatting tasks which do most of the work for you.
Cuberok is a music player and collection manager with a lightweight interface. It supports music collections, CUE sheets, Shoutcast/icecast streams, a Last.FM and Libre.FM scrobbler, downloading images for albums and artists from Last.FM, information about artists from Last.FM, and lyrics from LyricWiki.org, automatic ratings for songs, and support for many playlists at one time.
XMMS2 is a redesign of the XMMS music player. It features a client-server model, allowing multiple (even simultaneous!) user interfaces, both textual and graphical. All common audio formats are supported using plugins. On top of this, there is a flexible media library to organize your music.
AudioMove is a handy GUI-based batch audio file converter/copier program. It can convert various audio file formats to WAV or AIFF format (using libsndfile), and do high-quality sample-rate conversion at the same time (using libsamplerate). It is multi-threaded for maximum throughput, can handle thousands of files per batch, and does recursive directory scans.