xmms and xmms2
Very similar to Winamp, xmms has the ability to play most major audio formats. It also supports skins and plug-ins a-la winamp. Xmms is a relativly simple x application that uses plugins to decode media files, and then talks directly to the sound system ALSA/OSS or to a sound daemon ESD or aRTSd.
Xmms2 is a modular client/server re-write of xmms. Xmms2 can play back steams and talk to media servers, e.g. a daap daemon.
Xmms is mature with little change over the past few years, whereas xmms2 is still in development.
"Zinf Is Not FreeA*p". Zinf is a simple media player descended from FreeAmp. It runs on Linux and Windows, though the Windows binary on the Zinf site is lagging behind the Linux version. Like xmms it can playback most audio formats, and is skinnable. Like Xmms it can output to ALSA, OSS, ESD or aRTSd. Binaries for Debian are in Sarge, Etch and later have lost Zinf
A great GTK based tool for playing and organizing your music collection. Supports a multitude of formats. Very useful for large music collections because of its ability to maintain many play-lists. Also has a good search function. Has a similar feel to Apple's iTunes client.
Command-line mp3 player.
amaroK is a modern KDE audio jukebox application, under active development. Formerly amaroK could use various audio engines, at the moment it currently uses only the xine engine, with output to either an ALSA or OSS sound interfaces. amaroK is really a music organiser, and can be used to organise files local or remote, and talk with various audio stream servers. It has features a plenty - some say too many, however while it may not be the official KDE audio player, it is the default one.
Audio and Video
Fundamentally a library for media playing, which supports a very wide range of media formats including DVD, VCD, MPEG, AVI, Quicktime. Supports third-party codecs for things like RealMedia and Win32 codecs for things like WMV on x86.
Skinable X GUI for xine. Also gxine.
KDE GUI to libXine (see above). All the power but with a more familiar interface (if you're a KDE user).
Ability to play most video formats and DVD's.
It is probably best not to use pre-packaged versions of mplayer that are shipped with your distribution, since they are usually heavily restricted in the codecs that they can ship. There are some pre-packaged "full" versions available unofficially for some distributions:
- Debian: Christian Marillat
- Red Hat/Fedora: Mplayer's home page?
Freevo is an ongoing development to create TiVo-like functionality on a PC.
VLC (was Video Lan Client)
The VLC is a portable multimedia player for various audio and video formats (MPEG-1, MPEG-2, MPEG-4, DivX, mp3, ogg, ...) as well as DVDs, VCDs, and various streaming protocols. It can also be used as a server to stream in unicast or multicast in IPv4 or IPv6 on a high-bandwidth network. It's open source, and binaries are available for a wide selection of platforms.