Gloria from Vision of Escaflowne.
While I didn’t really care all that much about the movie itself, I did love the soundtrack; very rich and elaborate despite being for an anime (not trying to knock anime down of course). You just typically don’t hear something this…formal or well put together for an anime sound track. Blood + is one of those exceptions but then again, the composer/musician was Han Effin’ Zimmer. It’s no wonder it’s equally as exceptional and extravagant as this OST.
It should be noted I absolutely love Gregorian Chanting and Hymns. Combined with a full orchestra and you have the workings of a masterpiece.