Winamp. Small. Easy. Simple.
Or if when you close it you keep getting errors, just use itunes.
My favorite feature with winamp is its loadable playlists. Can load whatever you want organized however you want by simply loading up the playlist of your choice. Meaning you only have to add to your library once per list creation. I know its like this with several other players, but winamp seems to function the best with it. I don't think Itunes has that at all. All Itunes playlists are based off of mp3's in the library, which I hate. I could be wrong about this, I just don't put any effort into Itunes aside from loading the library to my specs each time I use it.
"They're everywhere, the little harlots."
-Martyn