Foobar2000 is an advanced audio player for the Windows platform. Some of the basic features include full unicode support, ReplayGain support and native support for several popular audio formats.

Features:
Audio formats supported natively: MP1, MP2, MP3, MP4, MPC, AAC, Ogg Vorbis, FLAC / Ogg FLAC, WavPack, WAV, AIFF, AU, SND, CDDA, WMA.
More audio formats supported through optional components, official or third-party.
Full unicode support.
Customizable user interface layout (new in version 0.9.5). View screenshots...
Advanced tagging capabilities.
Support for ripping Audio CDs as well as transcoding all supported audio formats using the Converter component. Read more...
ReplayGain support - both playback and calculation.
Customizable keyboard shortcuts.
Open component architecture allowing third-party developers to extend functionality of the player.