I absolutely love visualizations while listening to music, its unfortunate that Ubuntu does not currently have many presets, Fortunately here is a quick way to enjoy a few other visualizations in Ubuntu, personally I think these visualizations should have been installed by default with Rythmbox!
There is an interesting class of programs: audioplayers. What we expected from them? Playing music. What is required for this? Codecs, simple interface, playlist, equalizer. May be themes and control from keyboard. Many things can be applied to it, but audioplayer must stay a-music-player. This is primary task for such kind of program, and afterwards - cataloguer, tag converter, music collection organizer and so on. For this, spartanians and ancient-lovers remembers and likes simple yet powerful XMMS.