Vorbis Software Players

Here is a list of media players for various OSes that comes with "out-of-the-box" support for Ogg Vorbis.

Windows

WinAmp: very popular player supporting many formats
Foobar2000: freeware player with complex options and support for Ogg Vorbis, MP3, WAV and more.
Quintessential Player: Freeware player with support for Ogg Vorbis, MP3, WAV and Audio CDs. Also includes CD Ripping.
wxMusik: Open Source player with support for Ogg Vorbis, as well as MP3, WAV, AIFF and WMA. Makes use of an SQL based media libary for quick searching.
Coolplayer: very small Open Source player
dbPowerAmp: player suite
XMPlay
Ashampoo Media Player+: Audio and video player
DeliPlayer:
MediaJukebox: Audio management
MuzikBrowser: Player designed for display on a TV screen
MusicMagic Mixer: Player with playlist management
MediaPortal: Open source home theater software
MPEG Audio Collection: Organizer for music collection
Zinf: Zinf Is Not Freeamp, freeware player

VLC Media Player: Open Source player that support virtually every video and audio format.
Mplayer: Open Source video player that supports also many audio formats.
JOrbisPlayer: Java Player that uses the JOrbis Java decoder
jlGui: Winamp clone for Java
Zinf: Open Source player with support for Ogg Vorbis, as well as MP3, WAV and Audio CDs.
SnackAmp: Tcl/Tk player
HelixPlayer: Open source player from RealNetworks
RealPlayer: Commercial player from RealNetworks
Microsoft Windows Media Player: Freeware player from Microsoft. Runs on both Windows and Macintosh platforms.

XMMS
Rhythmbox
JuK: Open Source player for KDE with support for Ogg Vorbis, FLAC and MP3.
amaroK
Muine: Open Source player for GNOME with support for Ogg Vorbis, FLAC and MP3.
wxMusik: Open Source player with support for Ogg Vorbis, as well as MP3, WAV and AIFF. Makes use of an SQL based media libary for quick searching.
MPD: Music Player Daemon is a sound server that supports different clients. Supports many formats, among them Ogg Vorbis and FLAC
AlsaPlayer: ALSA audio player - "First player worldwide that did perfect reverse Ogg playback!"
Sonic-Rainbow
Cplay: Curses frontend for ogg123, mpg123 etc
Xine: Video player with long list of supported formats
Noatun: KDE audio player
CAJUN: Car audio system
GiantDisc: Jukebox system that can be controlled by a Palm
s.q.u.e.l.c.h.: Vorbis only player
MythTV: PVR project
Beep Media Player (a.k.a. BMP): XMMS fork that uses GTK+ 2.x and is compatible with both XMMS and Winamp skins
GQmpeg: GTK frontend for mpg123/ogg123 etc
BossOgg: Jukebox system
Gmerlin:
PyTone: Python-based jukebox player

Whamb: Freeware player with support for Ogg Vorbis, MP3 and Audio CDs.
For Mac OS X, here's a QuickTime [Export Component].
- reported orphaned, broken on sourceforge project forums.
- New version for Quick Time 7 and later.

The GP32, an arm9tdmi portable console with much hackability (gcc3 toolchain, expandable memory), has several Vorbis players available.

The Zaurus, a very flexible PDA which runs Linux, can play Vorbis files with a variety of software, including a plugin for the default media player, xmms, ogg123, mplayer, or theKompany.com’s tkcPlayer.

The Xbox Media Center is an open source project that transforms a modded Xbox with Linux into a media center and streaming client.

The Media Digital Media Player is a streaming client solution for the Playstation 2.

Pocket Tunes: Commercial software: $14.95, free 15-day trial.
AeroPlayer: Free for Ogg. Mp3 Support costs $20.00.
POggPl: A free open source player, that is still in alpha-stage.
The Magic Lantern: Another open source player in alpha-stage.
The Core Pocket Media Player: (Formerly BetaPlayer) Open source media player that uses Tremor also available for Palm OS

Conduits Pocket Player: Commercial player, free evaluation available.
GSPlayer: This is a free player.
PocketOgg: Open Source player that uses Tremor
PocketMusic: Commercial player.
The Core Pocket Media Player: (Formerly BetaPlayer) Open source media player that uses Tremor

For hardware "mp3-players" that support Ogg Vorbis see VorbisHardware