All the sound isolation threads I have read always suggest the same basic thing. Room within a room.
If you are going to put up stud walls to insulate then your half way there. Just make sure that the studs you put up do not come into direct contact with the block wall. Don't screw, nail or glue them to the cinder block. Attach them to the floor and ceiling and that's it. There is also a tube of sound proofing glue/calk that you can apply to the studs before you put up the drywall or OSB.
~Everyone has the strength, few possess the will~