simple player is mplayer/mencoder mplayer to play them and mencoder to make avi.mkv,ogg etc etc
konq or even mc in konsole I just double click and it opens the avi,wmv etc and hit f for full screen. my /etc/mplayer/mplayer.conf has vo=xv ao=oss etc.
no need for any gui front end ;D althou I do compile it with --gui and have 4 skins but that in my build script and no big deal.