Well, I use xine for playing movies (you need the xine-ui package), but my experience says that mplayer works better on suse like distros (and xine is better on debian based ones). For playing music I use audacious, it a simple, winamp2-like player, it uses winamp 2.x skins and has no music library. If you a need a more complex music player (with music library), you should try amarok. Also you can check out kaffeine, its a simple, yet powerful player (plays both movies and music as xine does, and amarok doesn't). The best way to find out which one is best for you is to try them all.
You can also check wikipedia for player comparison. Link here