you can go to Brahms, Dvorak, Bruckner, Mahler
Good suggestion to start with Beethoven - try his Emperor piano concerto and symphony #6 (pastoral)for starters.
And don't forget Tchaikovsky, Wagner and Sibelius !
The OP lists some sonically outstanding recordings from Fritz Reiner and the Chicagoans - to that group you can add Also Sprach Zarathustra by Richard Strauss.