Winamp whoops the Llamas butt, but like i stated before, if you use the command line version of
Mplayer you can do tons more. Like for instance, build a play list from a dir of files (movies, mp3, etc.) and play them all in one shot! (the GUI version only sends commands to the command line version based on your input.)
Another thing is that Mplayer uses config files that are just plain text so you could append or alter those config files per your needs. ...You can also stream internet radio from Mplayer. ...You could theoretically, build your very own AutoLisp GUI version of a movie, music player. Now that would be cool!