We used Roxul Safe n Sound for our media room and between the ceiling joists.
The amount of sound transmission is vastly reduced. With 2x12" floor joists we had enough room to put up a couple of layers of batts with air pockets in between.
The sound control is great (note this is not sound proofing).

http://www.roxul.com/sw18169.asp

"Those who preach the myths of audio are ignorant of truth."