One of my very favourite choral pieces is Rachmaninoff's Vespers (more accurately, the All-Night Vigil), where the great man was able to write a stunningly magnificent series of pieces within the Orthodox restrictions (more or less). Here he does it again, with his wonderful version of the Liturgy of St. John Chrysostom, actually written before the Vespers, In it, he combines ancient church chants with his own compositions - but the Church promptly forbade its performance in church because it was too modern and too expressive!
Expressive it certainly is, with the lightness of sopranos pitted against the deep rumbling basses which only the Russians seem to have. There is little variation in tempo, which may not suit everyone, but there is this glorious, continuous sound, sometimes rising to mighty crescendo, sometimes descending to whisper-quiet. Gorgeously and thrillingly sung. You can just picture yourself in a dark Orthodox church, smell of incense in the air and this reverberating off the walls. If you like this kind of music (and I suggest you try the famous Sveshnikov version of the Vespers here:
to find out), this is for you.