SilverWook said:

No "mono movie" mode like Yamaha amps have, or one to spread the sound around your speakers? What do you do with an old movie that hasn't been remixed?

This is what the Encoding Guidelines says for mono on the DOLBY site:

Decoders output 1/0 mode (mono) signals to either the Center channel or Left and
Right channels when the Center channel is not available. It is unnecessary and
therefore not recommended to encode mono signals in 2/0 mode.

Many recievers have a listening mode, on mine it is called direct, that bypass all effects and surround settings so that the audio remains as close to the source audio signal as possible. If you don't have it, you could just change your setup and tell it that you don't have a Center speaker, then it will automatically steer the mono to both L and R speakers. The quality of that sound is of course dependent on the quality of the receiver doing the steering to the fronts.