Off the top my head, I would have to say:
Beethoven’s 1812 Overture, I cant here that without thinking of Caddyshack
The Girl from Ipanema, that will forever be the song playing in the elevator scene of The Blues Brothers
“Thus Spake Zarathustra” and “The Blue Danube” in 2001.
“Singing in the Rain” and “The William Tell Overture” in A Clockwork Orange.
“The Mickey Mouse Club” in Full Metal Jacket.