What's that really famous piece of music from Quadrophenia?

Answer 1

The movie was actually based on the Who album by the same name. Here's the soundtrack:

The Who - I Am the Sea
The Who - The Real Me
The Who - I'm One
The Who - 5:15
The Who - Love Reign O'Er Me
The Who - Bell Boy
The Who - I've Had Enough
The Who - Helpless Dancer
The Who - Doctor Jimmy
High Numbers - Zoot Suit
Cross Section - Hi Heel Sneakers
The Who - Get Out and Stay Out
The Who - Four Faces
The Who - Joker James
The Who - The Punk and the Godfather
James Brown - Night Train
Kingsmen - Louie Louie
Booker T. & the MG's - Green Onions
The Cascades - Rhythm of the Rain
The Chiffons - He's So Fine
The Ronettes - Be My Baby
The Crystals - Da Doo Ron Ron
High Numbers - I'm the Face