In reply to The Lemming:
OK, time for my nomination.
Now this one needs to have the scene set, because you just had to be there to get the spine tingling impact that can never be done justice with Youtube.
Many moons ago I visited Iona and was aimlessly wandering through the cloisters of Iona Abby when I heard Gabriel's Oboe playing. Naturally, as the music was perfect in every way, I thought that it was being piped through speakers. It wasn't until I turned a corner that I witnessed the delight of two people playing this piece on a grand piano and oboe. They were just practising for a service to be held in a day or two.
I've loved this soundtrack from the very moment I heard the opening credits of the film The Mission, but to hear the notes serenely drift along empty cloisters of an island abbey, was in my mind ethereal.
And if you have the time or inclination, here's the whole lot in one go.
http://www.youtube.com/watch?v=B5LHUipN5U4&list=SPEC76378BECEF08A3