Saint-Saens, for several reasons:
Symphony #3 in C minor, “The Organ” - also used as incidental music in “Babe”. Listen to all of it, including the slow movement which is where the organ first appears, providing a softly-booming ground bass a few octaves below the strings.
The Carnival of the Animals. “The Turtle” is a joke - it’s the Offenbach can-can played very slow. “The Elephant” is also a joke, it has ballet music (I forget which) played on the double-bass. “The Swan” is sheer painting by music and showcases the 'cello as a solo instrument.
Bacchanale from “Samson and Delilah”. Wild, tempestuous, savage, barbaric climax to a dance that begins softly and sweetly; slave-dance music if ever I heard it, with a clever hint of the middle east. You should like this if you liked the Sabre Dance.
Danse Macabre. Listen to the Devil tuning his fiddle deliberately off-key at the start, all the way through to a sudden cock-crow when the dance is at its height and he has to let the tormented spirits go back to their rest.
Other stuff:
Modest Mussorgsky: “Night on Bald Mountain”. Not unlike “Danse Macabre”, except that this time is the ringing of the church bell that signals an end to the unholy revelries.
Mascagne: “Intermezzo” and “Easter Hymn” from Cavalleria Rusticana.
Beethoven: Symphony #6, “The Pastoral”. Tells a story of a day in the country, from the arrival, a hot and peaceful noon, a rustic festival in the afternoon interrupted by a thunderstorm, and a song of rejoicing after the storm.
Haydn: “Trumpet Concerto”. One of these days I may even be able to play it.
Widor: “Toccato” from “Symphony #5”. If you liked the Bach Toccata and Fugue you should love this. Proof that the pedal-keyboard of a pipe organ is a solo instrument in its own right - this should test your woofers as thoroughly as it tests the organist’s musicianship. It’s worth shopping around for a good recording as an organ with muy cojones makes all the difference to this piece 
Mendelssohn: “Violin Concerto in E minor”.
Schubert’s “Unfinished” Symphony. Who’d pay for a symphony with only half the movements completed? Quite a lot of people actually. Listen and enjoy.
Brahms’s “Academic Festival Overture”. Music with a history: He forgot to say thank you when he was awarded an honorary degree, and he made amends by writing an opera-type overture around some popular student songs.
Berlioz’s “Symphonie Fantastique”. Another story. It’s an artist’s opium-dream, in which he meets a beautiful young lady, dances with her at a ball, woos her and murders her when she rejects him, is marched off to the guillotine (and has a vision of her the moment before the blade falls) and joins the souls in torment in a graveyard complete with “Dies Irae” and a cracked French church-bell.
And much, much more…