I don't like to play games so for me normal level is 93db or so and a typical Fri/Sat night jam session runs up to 110-112db on peaks. I'd go higher if I thought I could get away with the neighbors not knocking on the door. They should probably be thankful I have not purchased a sub just for that reason.
I'm guessing that those who are able to enjoy listening at under 80db must have a very quiet noise floor in the room to begin with or have very sensitive hearing.
The noise floor in my room is quite high though in general. Using REW I measure a constant 50-55db at all times without a peep from anything else taking place. 116yr old house, no insulation, about 30ft off a a busy street.