When I was burgled many moons ago they took lots of stuff - but left a then brand new MX5500 and new BC8500. The only B&O item they took was the phone. As Peter said the MX was probably too big to take but I'm still suprised they didn't take the Beocenter. I figured at the time they probably thought it was some sort of food warmer
and went for the better items.
I guess my burglars were as stupid as yours but it's still a horrible invasion of privacy - hope you didn't lose any sentimental items. Get an alarm installed immediatly and use timer lights when you are not at home. I was told by the police that they quite often come back for seconds.
If you think nobody cares, try missing a couple of payments.