Funny, I use debian as well, but I've always had issues getting mplayer to
behave intelligently. It works, but I end up with this weird thing where
it will refuse to fullscreen. I've managed to get to work a few times, but
it's not as simple as say, just apt-get install xine-ui totem w32codecs,
which seem to have intelligent defaults for controls, and handle any file
I throw at it (short of real player crap).
Although to be fair, if you don't grab the w32codecs deb package (it's
somewhere on apt-get.org) pretty much nothing works. I think there's also
something you have to run for DVDs to play properly... but I don't have a
DVD player, so I can't really comment.