I'm not familiar with the War Requiem.  After reading so many endorsements
on this list, I'm anxious to acquire a recording of it.  With that
disclaimer, I'd like add that Schnittke is one of my favorite composers.
I particularly like:

   1st Cello Concerto
   3rd and 6th Concerti Grosso
   2nd, 3rd, and 4th Violin Concertos
   In Memoriam (for Orchestra)
   Music for Piano and Chamber Orchestra (the last movement is a real riot)

I think all of this music was written after 1960.  There's still a lot of
Schnittke I'm not familiar with.  With time, that will change.

Also:

   David Del Tredici's "Final Alice"
   Messiaen's Concert a quatre (1991). The Vocalise is quite beautiful.
   Works by David Diamond (e.g Symphony no. 11, written in 1991).

Mike