which opeth song is a "classic"

It's hard to pin down specific songs as classics, seeing as most of their songs are well above average. But in my eyes, the whole Still Life album is classic, as well as "When", "The Drapery Falls", "Dirge for November", "Advent", and "Nectar" (I'm not really too keen on Orchid, and haven't listened to it much, but once classes end I'll take the time to really listen to it)
 
you're all putting your fave tracks, thats not what was asked (i dont want to sound like a goddam teacher though)...i'll go with black rose immortal: it has all the elements opeth brings together...acoustic guitars, death vox, clean vox, heavy riffs, long guitar licks, amazing lyrics...