If you're looking for something minimal I recommend Vox (http://voxapp.didgeroo.com/).
There's no database that songs have to be added to, it's just whatever the file/folder structure is for your tracks.
One idea I experimented with was using pytagsfs to mount a virtual file system based on ID3 tags. I could never get it to work though, and the last update to the project was 2009 :(