I vote for .....The Moor...
I love BRI, but feel it does not flow as well as a long song should....even Crimson, a longer song, feels more like 1 song then BRI..of course, that takes nothing away from how great it is, but I do not like the idea that a great song like BRI, is pushed even higher by some just because it is 20 minutes long (I in no way am saying the above people are doing this, but I have met people who feel this way...that it is long, so it rocks)
So anyway, I must vote for a song that I would not even put in my top 5 Opeth songs...but it still ROCKS..it sets the mood for Still Life, the album that took me the longest to get into from Opeth (well I still have not gotten 100% into BWP, but I am not sure if I ever will)