Peyote is an audio player with a friendly MC-like interface. It is designed specifically to work easily with cue sheets. It plays wv (wavepack), WAV, FLAC, APE, Ogg, WMA, and MP3 formats. It supports ID3v2, APEv2, FLAC, and Vorbis tags; multiple playlists; and tabs. It can copy, move, remove, and rename files.
Neformal is a small audio player with a file manager and the ability to play file by file. It can keep bookmarks for favorite directories. It can compute RMS statistics for 16 bit PCM WAVs. Song lyrics are supported (via lyricwiki.org). Drag and drop can be used to interact with other applications. ID3v1 and ID3v2 tags are handled flexibly. The charset for tags can be selected. There is a built-in viewer for images and text files. The output device can be selected.
ifpgui is a Linux GUI for the iRiver iFP flash portable player. It is similar to the iRiver Manager for Windows and supports upload, download, delete, rename, device status (battery status, etc.), tuner, and playlist uploads. It supports the iFP-100, iFP-300, iFP-500, iFP-700, iFP-800, iFP-900, and possibly the N10 series. It uses a pure Qt programming interface.
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.
Mixxx is software for DJs that provides everything needed to create live mixes. It allows you to beatmatch songs and crossfade them together, like you would with turntables and a mixer. It runs without any extra hardware, and offers a wide range of advanced features including comprehensive MIDI controller and vinyl control support. To obtain the lowest latency and highest responsiveness, it uses hardware video acceleration and takes advantage of multi-core CPUs.