I'll cover the "Demon of the Fall - best Opeth song?" or whatever thread here as well...
not Demon of the Fall. Bitchin' song... not the best. If I wanted to show someone "this is what Opeth sounds like" in 6 minutes or less... Demon would be my best bet.
In the poll, I said "Black Rose Immortal" (which is the easy choice, 'cause it's so long, not that length has anything to do with it or anything, but anyways...) and I don't think I can give a different answer now.
It's probably the toughest question to ask an Opethian. Even if I could say "MAYH in it's entirety is my favourite Opeth song" that still wouldn't be enough to sum up Opeth, and it's the best album I've ever heard.