Not really the same genre, but I like listening to orchestra/choir/opera musics from different media (movie, anime, games, etc.)
More opera:
Diva's song : From Blood+ anime, voice starts at 1:25. By Mark Mancina and Elin Carlson.
Voyage to Avalon : From Avalon movie. By Kenji Kawai and Elzbieta Towarnicka.
More choir:
2H of Ghibli orchestra : From Joe Hisaishi. Not all of them have choirs, but the one with choirs are great and have a lot of chorister (?)
Dancing mad: From FF6, One winged angel: FF7, Maria and Draco/darkness and starlight: From FF6 (you probably know them, and they have a lot of different versions in different languages)
Church:
Ave Maria, from Cowboy bebop
Hallelujah, from Song to Fly
It's not what you are looking for, but they are choir and orchestra.
If you like choirs, maybe you can check actual specialized choirs groups like
The Red Army Choir
If you like Acappella songs, you could like Corsica chants which are sung by a group of male voices (Edit: and Peter Hollens on youtube too)
Check this Celtic (and French minstrel/medieval) style :