Audacious Music Player
I've been using the Audacious Music Player recently. It's much more lightweight than Clementine, which has features I don't always need. I was impressed that Audacious has some intelligent and sane default behaviors out-of-the-box that don't require much reconfiguration. For example, it doesn't mess with the "playlist" tabs I reserved for internet radio stations when I open a local music file.
Audacious also has an extensive set of default plugins readily available in most linux distros, just the stuff I need (e.g. FLAC and .cue sheet support).
However, I'm looking for more good plugins, especially visualization (I've yet to see any that would include the album art and song info). So if anyone has any recommendable ones, tell me please. :)