Mozart's Requiem is just amazing!! One of my favorites also from Monteverdi:maxtree said:Here are my favorites :
Jordi Savall and Montserat Figueras : " Le royaume oublié, la tragédie Cathare " ( the forgotten kingdom)
Mozart " Requiem"
J.S. Bach : as good as everthing. "Godberg variationen" and " Das wohltemperierte klavier " on clavicord not on the piano
Monteverdi's " Vespero della beata virgine "
Purcell " Dido and Aneas " with Andreas Scholl. I am also a great fan of Philippe Jarousky, a counter tenor too.