I’ve been using iTunes, recently, to play my music. It’s quite a nice interface; it’s sad, however, that it’s crippleware. It doesn’t include other peoples’ shared music in its "recently played" or "most played" lists.
It also lacks a "watch directory" option; if you add music to a directory, you have to add all the files individually: add the directory, again, and everything becomes duplicated. Picasa has this, why not iTunes?
Originally published on my old blog site.