Some parts here and there on all the five albums, but I believe Face of Melinda is the only song I dare to sing all through.
Apart from Opeth, "Black Tears" by Edge of Sanity is one of those songs I always sing along. Actually, when the cassette-player of my car broke down and I had to drive hundreds of kilometers in silence, I just sung: "This fluid on my cheek / it drains me, I get weak / my heart is cold and bleak / black blood, black tears..."
-Villain