I like foobar for music and GOM for video.
itunes to me would be the best if it didn't cause conflicts for me with ConvertXtodvd, wasn't such a memory hog and could retian links when I move or rename files.
songbird is amazing and I'm cheering heartily for it. But for a year now I have been installing the latest hoping it will be stable enough to use in real life, and so far no.
atunes has some pluses too for the itunes crowd.
and for video, GOM is easy to use and trouble free, looks nicer than VLC, and plays everything.