Some high school must reads include:

Steinbeck's Winter of our Discontent
Fitzgerald's The Great Gatsby
Malamud's The Fixer
Salinger's Catcher in the Rye
Knowles' A Separate Peace
Melville's Moby Dick and
Joyce's Portrait of the Artist as a Young Man.

I'd also throw in Verne's The Mysterious Island.

Nothing wrong with a junior or senior reading The Godfather, a perfect summer read, and the basis for the greatest cinematic achievements.