Charles Ives, the first symphony.
Absolutely anything by Anton Bruckner, but especially the symphonies (especially #6!) and the Mass in E minor.
Mozart's Concertos for French horn, but then, really, any Mozart.
Beethoven's Ninth Symphony, just because.
I love Renaissance choral music.
Handel, Vivaldi, Bach are beloved.
Rossini's overtures.
Montiverdi's
Orfeo.
Right now I'm listening to Vivaldi's Concerto in G Major for recorder and strings, and the largo is gorgeous.
Okay, I can't pick favorites.