
Almost everything they wrote, but some good starting points:
Chesterton - Heretics, Varied Types
Hazlitt - The Plain Speaker, Table-Talk
Emerson - Essays: First and Second Series
Stevenson - Virginibus Puerisque, Across the Plains
Santayana - Little Essays ed. Logan Pearsall Smith
Russell - Unpopular Essays, Sceptical Essays
Mencken - Selected Prejudices
Wilde - Intentions
James - Talks to Students, Memories and Studies
I'll recommend Sceptical Essays, Unpopular Essays, and The Conquest of Happiness (all by Bertrand Russell).
If I had to pick just one for you - Voltaire's Bastards.
edit: Also La Rochefoucauld's Maxims should be very high on a list of exposés - it's a savage exposé of oneself. La Bruyere's Characters is a milder but still at-times-scathing exposé of the world. As is Fable of the Bees..
SARK's first 4-5 books, Robert Fulghum's books, Emerson's essays, Hazlitt's essays, Bertrand Russell's essays (e.g. Sceptical Essays, Unpopular Essays), GK Chesterton's essays and his book Heretics, Nietzsche's books, William James' essays, RL Stevenson's essays, La Rochefoucauld's Maxims, La Bruyere's Characters, Kurt Vonnegut's The Sirens of Titan, Ben Zander's The Art of Possibility...