Ottorino Respighi - The Atalanta Symphony Orchestra recording of his three "Of Rome" works is excellent.
I will also second Holst, Mussorgsky, Brahms and Wagner. Oh, and keep in mind, there is always more Beethoven to hear! He is an obvious example of profound composition for a good reason, and researching his works always provides a good exercise in discovering great music.
Steve Reich, Edgard Varese, Philip Glass, George Gershwin, Arnold Schoenberg, Richard Strauss, Sergei Prokofiev, Modest Mussorgsky, Richard Wagner, Karlheinz Stockhausen
i like J.S Bach a lot, so far hes my favorite
of the Mozart i've listened to, i'd say i liked 47% of it
i like Bethoven's Moonlight Sonata and Schubert's Ave Maria
i've listened to some others, but im kinda new to it.