Every band or genre has moments that make it special. I'd like to know what you consider defining moments of a band or just a genre as a whole. Here's some of mine...
The "Celestial Voices" section and Roger Waters's gong playing from "A Saucerful of Secrets" in Pompeii
Echoes. All of it.
"Funky Dung" from Atom Heart Mother
The talk box solo from "Pigs (3 Different Ones)"
Part VIII from "Shine On You Crazy Diamond"
The scream from "Careful With That Axe, Eugene"
The opening from "Sorrow"
The spoken opening from "Great Gig In The Sky"
The two solos in "Comfortably Numb"
Breathe (Reprise) from "Time"
The hammer sequence from "The Wall" film
The helicopter sound at the beginning of "The Happiest Days of Our Lives"