I'm taking ancient philosophy at a public university. I've engaged with the Western canon from the pre-socratics through Aristotle, a number of the medievals and a smattering of modern philosophers including Kant, John Stuart Mill and Kierkegaard.
I find myself feeling very inadequate, however, when it comes to ideas that might be considered "postmodern". I'm not content to keep yapping about the objectivity of truth, however strong my convictions on that subject might be. I'd like to understand the jargon that is used alike by my sociological, linguistic and philosophy professors (the latter in unguarded moments).
Who are the key figures I should read to best understand philosophy during the last century and a quarter?