The first three or four tracks on there are my choice combo. But you could fill in just about any Grouper, Gregor Samsa, Peter Broderick, Eluvium, Goldmund, most-things-from-Rune-Grammofon (In The Country, Skyphone, Svalastog, Biosphere?), anything Leylard Kirby has done, anything Christina Carter has touched, Beans (the Vancouver post-rock band, not the rapper)... Hrm.
But also, this one always got me when I was a kid:
Some how I can't get my head in the game, despite listening to nearly all of the above tracks. Big ups to @icelandbob for brilliant 80s tracks that I'd never heard before yet felt like I had and to @lampcommander for mondo excellent mo betta blues. Robert Johnson I'd never heard before is hard to find!
So for the request at least half if not more of Dead Can Dance's discography suits but I'll go with the one that has struck me deepest and longest. It's a poem, what 200 years old now? And I didn't know that until just a couple of years ago. I just thought Lisa Gerard was singing about the lovely Irish countryside for which her protagonist chose to fight, even as it became soaked in blood. Now that I think about those haphazard barely fields as the gravemarkers of rebels from years earlier my heart breaks all over again "when e'er I think on Ireland dearly." And I've never been!
To quote Wikipedia - The Song of the Sibyl is a liturgical drama and a Gregorian chant, the lyrics of which compose a prophecy describing the Apocalypse, which has been performed at some churches of Mallorca (Balearic Islands, Spain) and L'Alguer or Alghero (Sardinia, Italy) in Catalan language on Christmas Eve nearly uninterrruptedly since medieval times.
Was going to post, but there's already some Dead Can Dance and some Silver Mt Zion up here! Here are some others - they've all got that quality I reckon, either in bits or in spades.