The Closing of the American Mind

Being a programmer, you've probably felt the appeal of Platonism, so I'd recommend a couple of his dialogues: Phaedrus, Symposium, and the Republic (in order of length, short to long, since they are pretty dense). I'd also recommend reading the Republic last, so you can get over the misconceptions you were probably taught in high school. Allan Bloom's Closing of the American Mind is also very enlightening for a) understanding the goals of the enlightenment, and b) understanding the current state of our culture.