Insulation between floors - how affective?

My home theater System is in a room on top of a hot water baseboard heating system in the basement.  So every time the boiler fires up and the pump is circulating water I can hear it.  Very annoying. Also my air conditioner compressor sits on the other side of the exterior wall but not much I can do about that.

 Anyone use insulation batts to stuff in the basement ceiling rafters to deaden sound. Rockwool/roxul has some sound reducing insulation batts that looks interesting.