Nemp, a short form for German "Noch ein MP3 Player" (Yet another MP3 Player) is a pretty lightweight and flexible MP3 player which competes nicely with other players which specialize in audio playback like Winamp. It is a free and open source music playing application that's powerful, customizable, straightforward, reliable and user friendly.
Here are some screenshots to illustrate the features and user interface of this application:
AIMP
Qmmp
Virtual DJ Free
MediaMonkey
Zortam Mp3 Media Studio