for a long time it was Advent, then it was Drapery Falls, now it's Baying of the Hounds.
I love the journey that song takes you on, and the last minute or so is among my favorite Opeth moments ever. amazing chord progression, just a hint of warmth coming through the thunder.
oh and Funeral Portrait/Patterns/Blackwater Park has to be one of the best successive trio of songs I can think of on any album, ever.