Can you whistle Gioachino Rossini's most famous orchestral work? Surprise: You can if you've ever watched The Lone Ranger.
Think back to the first time you heard the overture to Mozart's The Marriage of Figaro. Were you just a kid watching Willy Wonka and the Chocolate Factory in a dark cinema? Similarly, thanks to V for Vendetta, I can't hear Tchaikovsky's 1812 Overture without picturing a revolution, or Ravel's Boléro without thinking about Bo Derek "making love" to Dudley Moore.
It's hard to list all the pieces of classical music used in soundtracks that are now inextricably associated with specific events and moods, but here are some of the most ubiquitous of the bunch.
Richard Wagner's "Ritt der Walküren" ("The Ride of the Valkyrie")
Watch the scene—I dare you not to shudder. Every bit of Francis Ford Coppola's Apocalypse Now is frightening, but providing your own epic soundtrack while bombing an entire Vietnamese village is something else. In Die Walküre, the theme accompanies the Valkyrie sisters riding flying horses as they search for fallen heroes and ever since that it has become synonymous with battle imagery. "The Ride of the Valkyrie" appears in D.W. Griffith's silent film The Birth of a Nation, Stanley Kubrick's Full Metal Jacket, and even provides the tunes for one of Elmer Fudd's many hunts for Bugs Bunny.
Carl Orff's "O Fortuna"
When you hear this chorus, you know something's about to happen and it's going to be so. Very. Dramatic. Originally a medieval poem about fate, "O Fortuna" was set to music by Orff in the 1930s and has become a staple in epics, dramas, parodies, and even television commercials. Notably used in John Boorman's Arthurian film, Excalibur, Oliver Stone's Jim Morrison biopic, The Doors, as well as his 1994 flick Natural Born Killers.
J.S. Bach's "Toccata and Fugue in D Minor"
Walk into a dark Victorian (or Transylvanian) mansion and this is what you'll hear. It was prominently featured during the opening credits of Rouben Mamoulian's 1931 film adaption of Dr. Jekyll and Mr. Hyde. That's probably why this piece of organ music has become associated with everything eerie. Also heard in The Black Cat and Tales from the Crypt for obvious creepy reasons; parodied in Monty Python's The Meaning of Life, and outside the horror genre in Sunset Boulevard.
Mozart's "Eine Kleine Nachtmusik"
Mozart is the composer whose music has appeared most in films and this particular piece is the most popular. The allegro is usually set against posh affairs, but it appears to be infinitely more popular as a comic point of contrast—and who better than Ace Ventura in a mental hospital in a pink tutu to prove it?
Jacques Offenbach's "Galop Infernal" ("Infernal Gallop")
Okay, this tune may have been popularized by the can-can, but in Baz Luhrmann's Moulin Rouge it's used spectacularly. To convince the Duke to invest in an upcoming show, the troupe puts on an improvised song-and-dance set to a thumping interpretation of "Infernal Gallop". So exciting, the audience will stomp and cheer! So delighting, it will run for 50 years!
Léo Delibe's "The Flower Duet"