This was first posted by Craig73 under http://brainstorm.ubuntu.com/idea/17235/
and had 11 upvotes and 0 down before the idea was closed for being a dupe. I also felt it had many good points so added it here verbatim...
System beeps and really any application generated sound should have more contextual control.
a) Headphones are plugged in, so why are PC Speaker sounds being generated? Re-direct beeps to the headphones.
b) Movie profile - tone down or turn off most other sounds other than those for the video player
c) Entertaining profile - tone down or turn off all sounds. Sounds like incoming VOIP calls or IMs (from certain people) could perhaps be rendered as a background sound (that in a surround sound setup sounds off in the corner / noticeable but no disruptive)
d) Silent - turn off all sounds except the most critical. Perhaps those "beeps" should be showing up as flashing notifications at this point.