@anniemo
Lollypop looks nice and it supports album covers — just point it to where your music's at and it will arrange everything by artist/genre/album and will retrieve cover art and artist information from public sources — very easy to use.
But it's rather slow IMO, might become unresponsive if you're using an older machine.

I use cmus for music and it's very easy to use, but it might be… too much if you're not used to programs with text-only interface, and no cover art.
@gemlog @cosullivan