From the sweet lyricism of Fauré to the populism of Brahms to the theatricality of Verdi, requiems remain the favorites of singers, conductors, and audiences alike. We talked with Kathy FitzGibbon, director of choral activities at Lewis and Clark College and head of faculty at the Berkshire Choral Festival, about the enduring appeal of requiems and the modern interpretations they have spawned.