In my old apartment, -16 or -15 was just about right for most movies. In my new house, though, I find myself listening around -10 or more. The distance from the speakers is more or less the same, but I guess since the room is much larger it takes a bit more effort to create the same effect. One pleasant discovery in all of this is that my Marantz receiver barely gets warm.
As Randy mentioned, though, it really depends on how the source material was recorded. I put in my copy of "Stop Making Sense" the other night and had to turn it up to -5 or -6 to get a decent (exciting but not ear-splitting) level. With other movies I've backed it off to -12 or -14.
