Are you looking for a free and open source music player that you can use no matter which operating system you boot or switch to during the day? Meet aTunes, a small competitor to both Amarok and Apple's iTunes. Its name sounds like a hybrid of the two, and it tries to have a unique combination of the best of both user experiences.
aTunes is a Java-written, cross-platform music player. It supports a variety of common audio formats, including both open source and proprietary codecs, due to its MPlayer audio engine back end. Like many quickly evolving programs, it has a few issues, but the better outweighs the bitter.
aTunes appears to be inspired by both iTunes and Amarok. Like Amarok, its music management is playlist-oriented, and it uses a tabbed interface to browse between music, tags, podcasts, Internet radio, and MP3 devices. It integrates with Last.fm and Audioscrobbler, and supports "smart" playlists that, for example, select the highest rated or most played songs. There are some similarities between aTunes and iTunes as well. The overall user interface layout seems to reflect iTunes, and every window element (navigator, playlist, or context information) in aTunes can be shown as a separate window.