I nominate Louis Vierne, composer and organist at Notre Dame de Paris:
Vierne suffered either a stroke or a heart attack (eyewitness reports differ) while giving his 1750th organ recital at Notre-Dame de Paris on the evening of 2 June 1937. He had completed the main concert, which members of the audience said showed him at his full powers—"as well as he has ever played." Directly after he had finished playing his "Stele pour un enfant defunt" from his 'Triptyque' Op 58, the closing section was to be two improvisations on submitted themes. He read the first theme in Braille, then selected the stops he would use for the improvisation. He suddenly pitched forward, and fell off the bench as his foot hit the low "E" pedal of the organ. He lost consciousness as the single note echoed throughout the church. He had thus fulfilled his oft-stated lifelong dream—to die at the console of the great organ of Notre-Dame. Maurice Duruflé, another major French organist and composer, was at his side at the time of his death.