Foobar2000 is free, small(~3 MB), light on resources and simple to use. The interface is very user friendly and may not look attractive to many but a few changes using optional components can make it rock!
The best thing about Foobar2000 is that its SDK is under BSD license therefore allowing developers to develop their own components(plugins) for this application.
- Supported audio formats: MP3, MP4, AAC, CD Audio, WMA, Vorbis, FLAC, WavPack, WAV, AIFF, Musepack, Speex, AU, SND... and more with additional components.
- Gapless playback.
- Full unicode support.
- Easily customizable user interface layout.
- Advanced tagging capabilities.
- Support for ripping Audio CDs as well as transcoding all supported audio formats using the Converter component.
- Full ReplayGain support.
- Customizable keyboard shortcuts.
- Open component architecture allowing third-party developers to extend functionality of the player.
There are other good audio players in the market but Foobar2000 has carved a niche for itself with the users owing to its simplicity and good functionality. There are many useful functionalities such as audio converter, inbuilt file copy/delete/rename/move etc (now you don't have to open the folder for every song you want). If you haven't tried this yet, it is time for you to do so.
Download it from here
Read more about it on Wikipedia