A thing that I like in music: switching instruments. I love listening to Andres Segovia playing Bach's Cello Suites on a Flamenco guitar. I really enjoy Two Cellos playing pop music, or Apocalyptica doing Metallica songs on a string quartet. I think a version of Danse Macabre for violin, viola, and cello is one of the best versions of that tune I've ever heard.
I am also a big fan of human voice music. From the traditional choir a cappella and Jewish cantor, to barbershop quartet, to Tuvan Throat Singing, to Pentatonix,]; music that humans make with themselves alone (solo or in groups) makes the hair on my arms stand up. I love it unabashedly and unapologetically.
So in steps Samuel Barber. In 1936 he writes what is possibly the most haunting piece of American Classical Music of the 20th Century, and in 1938 Arturo Toscanini records it with the NBC Symphony Orchestra. It's a big hit, and cements Barber's early career as composer par excellence. And then, in 1967, Barber recomposes it, this time as a choral piece using the text of the prayer "Lamb of God" in Latin (because everything is prettier in Latin).
So that's Agnus Dei, which is heartrendingly beautiful. It's one of my favourite pieces of music.
Obligatory Youtube Link: http://youtu.be/UR-wEbZqT1c