Like Nick, I did some insulation between the ceiling raftors using the fluffy paper backed material which claimed to be sound rated. Our entire basement is an ICEBlock foundation, which includes foam in the inside and outside, with 8" of concrete poured in the middle of the rebar voids. Much better in many ways to just standard poured foundations.
As John mentioned, some noise gets upstairs, but I still am able to watch movies at a somewhat loud level and the kids don't complain, right above the HT room.
Not a lot is going to contain EpiCenter LFE from EP500's or 600's.
