It depends on many things...
size of room
reflectiness (eg liveness) of room
hearing subjective quality
quality of material being played
mastering level
For example, I listen in a very small room (3m x 2m) and I am relatively close to my speakers for that reason. The room is carpeted to the floor but has a lot of glass along one side. I listen to music below 60 generally for typical modern day mastered music. DVDs 70 or so.
In another house which had a larger room 4m x 4m, high ceilings, big curtains on two walls, I'd typically listen to the same music at 65. DVDs 75 or so. The Michael Jackson 'This is it' "concert" is quite comfortable at 85 because it has immense dynamic range and is beautifully produced.