Was going to say Firth of Fifth, but that's been taken, then was going to say Awaken but that's gone as well ..... and I know I'm only allowed one choice so I'll go for
Shadow of the Hierophant. Haunting vocals by Sally Oldfield at the beginning .... fantastic blend of instruments (although it's easy to say that about all Steve Hackett's compositions) then a long slow build up getting louder as each additional instrument instrument is introduced until the fade down after Steve's own Tubular Bell is introduced near the end. Why it's under 12 minutes long though defeats me .... could have been expanded to be a whole album by itself.
btw, and not a lotta people know this, it was co-written by Mike Rutherford but no matter how often I listen to it I can't find any Rutherfordesque parts of the track, to me is pure Hackett at his best.
