I saw them perform the Wall at earls court, when they built the wall on stage to about 40-50ft high. By the time Comfortably Numb came, the wall was built, and Waters and the band were these little dots at the bottom of the wall. Waters sings the verse I believe. Then for the chorus ( "there is no pain you are receding" ) and those wonderful harmonies, gilmore sings and I assumed he was on stage too. Then comes that guitar solo, surely one of the greatest ever, and suddenly the stage lights and auditorium lights are dimmed, and there standing on top of the wall, 50ft up, totally alone, is gilmore, guitar howling, one spotlight behind him, throwing his shadow over the whole of the floor of the auditorium. ( I was up to one side ). The only person lit in the whole arena.
Shiver. My favorite live moment by a mile.