Tonight I've started exploring choral music, and was particularly intrigued by Russian Orthodox basso profundo - specifically works by The Orthodox Singers and The Tallis Scholars.
I compiled a 16-disc catalog including Peter Phillips' sacred choral works, the indispensable Orthodox Singers album, Moscow Choral's compilation, the English Baroque Soloists' recording of Bach's Mass in B Minor, and the Moscow Chamber Choir's Liturgy of St John Chrysostom, as well as the BBC Symphony and the Vienna Philharmonic's performances of Mozart's Requiem.
If you can suggest any other choral essentials, I'm all ears!