So hard to select only one, after 37 consecutive years of watching & following international figure skating!
My choice:
"Barnum on Ice" free dance - Torvill & Dean - Worlds 1983, Helsinki
Honorable Mentions, in chronological order:
"Moonlight Sonata" LP - Protopopovs, 1968 Olympics, Grenoble
"La Valse" LP - Janet Lynn...don't remember the year, right now! 1971 Worlds, I think...
"Don Quixote" LP - John Curry, 1976 Olympics, Innsbruck
"Gershwin Piano Concerto" LP, first version - Underhill/Martini, Worlds 1983, Helsinki (I prefer this version to the 1984 one)
"Irma La Douce" LP - Liz Manley, 1988 Olympics, Calgary
Spanish-themed SP - Oksana Baiul, 1993 Worlds, Prague (I prefer this to her LP or the next yr's Swan SP)
"Thais Meditation" LP - Berezhnaia/Sikharulidze, 2002 Olympics, Salt Lake
"Doctor Zhivago" LP - Johnny Weir, 2004 US Nationals