You are correct. Nothing beats Hellfire. Gives me chills. Every. Single. Time.
This one's pretty good though:
The end gave me chills the first two times I heard it and then lost the same magic but it's still quite good. Be Prepared and Friends on the Other Side have already been mentioned, so that just leaves me with:
As much as I hate Ursula as a villainess, Poor Unfortunate Souls is fantastically chilling.