Soprano is a tiny (minimalist audio player) that runs in the systems tray. Soprano can be further controlled by hot keys. You can drag and drop music files or even complete directories containing your music to the program to add them to the list. Soprano supports the playback of MP1, MP2, MP3, OGG, WAV and WMA files. It's a great tiny Audio playback tool to add to your USB collection.
Authors Website: kimero.com.ar/soprano (appears abandoned)
Download: Grab this Portable Music Player
Notes: Extract the contents to a folder on your USB flash drive. Then simply run Soprano.exe to launch the program.