Exaile is one of the programs that nearly is constantly running, when my desktop PC is on. It’s my music player of choice. I’ve tried many over my Linux years. Rythmbox, Amarok, Aqualung (which also supports playlists in tabs), Listen, XMMS and some that may have been forgotten.
It has a customizable media library, tabbed playlists, lyric support (sometimes a little buggy) and it just fits my needs perfectly.
There are pretty up to date packages in the Ubuntu repositories, just:
apt-get install exaile
So if you have been looking around for something that is not fully overloaded or too minimal, give it a shot, it’s worth it.