mplayer is the real media player, but it comes without a GUI (Graphical User Interface), so if you want to use it, you have to use XTerm and command it (STOP, PLAY, FF, REW) through keyboard key. This is not user friendly of course, therefore there is some frontend that allow you to ignore the Xterm-way and use a more user friendly interface. One of this is KMplayer which is originally written for KDE using the QT.
Hope this is clear... if not, ask more ;-)