The Structure of Scientific Revolutions, Thomas Kuhn
The Apology of Socrates, Plato
Professionally:
The Pragmatic Programmer, Andrew Hunt and David Thomas
The Best Interface is No Interface, Golden Krishna
The former because it's an excellent introduction to one of the west's most influential figures (Socrates). As a testament to that influence, any philosopher before him is called 'pre-Socratic'. Not to mention Socrates' tale of traveling around Athens questioning the populace after visiting the Oracle is a great story. It wouldn't hurt to follow up with the dialogue Phaedo next, which details the end of Socrates.
The latter for many reasons. The Republic is the most complete statements of Plato's philosophy, in addition to being beautifully written (Plato's writing seems to shine through in just about any translation that I've seen, but the Allan Bloom translation is particularly enjoyable).
Plato, and this book in particular, have been extremely influential in western thought. Indeed, one philosopher wrote that "the safest general characterization of the European philosophical tradition is that it consists of a series of footnotes to Plato." And here in America, the founding fathers often quoted Plato in their pamphlets prior to seceding.
Following the dialogues in the book will take you from discussions on the nature of justice and reality, to the best mode of governance. It serves as a wonderful introduction to what it means to do philosophy and hopefully you find it as enjoyable as I have.
Homer: both the Iliad and Odyssey
Sophocles: Oedipus the King (read it - far better than you might think)
Plato: The Apology of Socrates
Sappho's fragmentary poems (the translation by Anne Carson titled If not, winter is especially good)
Dante: Inferno
Shakespeare: at least one tragedy, one history, one comedy and one of the final "problem plays"
John Donne: a bunch but if none else Elegy XIX To His Mistress Going to Bed
Philip Larkin: he didn't write much; read the complete poems (if nothing else, look at "Born yesterday")
T.S. Eliot: "The Love Song of J. Alfred Prufrock", "Return of the Magi", "Hollow men"
Ernest Hemmingway: A Clean Well-Lighted Place
Herman Melville: Bartleby, the Scrivener
Joseph Conrad: Heart of Darkness and The Secret Agent
Gustave Flaubert: Madame Bovary
George Orwell: Any and all of the essays, but especially "Shooting an elephant" and "A hanging"
Stendahl: Red and Black
James Joyce: A Portrait of The Artist as a Young Man
Andre Dumas: The Three Musketeers
Samuel Beckett: Waiting for Godot
Tom Stoppard: Rosencrantz and Guildenstern are Dead
I'll shut up, except to say that although I agree with some of the people on the thread that reading "great books" just because they're considered great is stupid, these books were all a joy. I remember them each pretty happily and return to a few of them now and again and just browse through for awhile. Some "great" books really are great, and if you're reading for yourself (not as a forced assignment), they're often well worth the effort (because, yes, none of them reads like a magazine article).
Apology of Socrates - Plato
The Betrayal of the Intellectuals - Julien Benda
(I doubt reading either Apology of Socrates will give an unambiguous reason why he didn't offer the exile option, if any reason.)
