Plato and Aristotle between them not only laid the foundations for Western philosophy, many would argue they divided it neatly between them: Plato the one who with his "Allegory of the Cave" gave birth to the idea of an existence beyond our senses, giving a rational gloss to mysticism. Aristotle, the father of logic and a scientist, with a this-world orientation. There's a famous fresco by Raphael, "The School of Athens," where that's illustrated, where the figure meant to be Plato points to the sky--the heavens--while Aristotle points to the ground--to this Earth. If you're going to ask me which school I belong to--at least as so categorized, Aristotle wins, hands down. Yet if you ask me which philosopher I found a joy to read, which a slog--well, Plato wins.
Unfortunately, much of Aristotle's works were lost, and what remains I've seen described as not his polished material, but "lecture notes." In the case of Plato, though, what we have are largely "dialogues." These are like little plays, with characters arguing back and forth. Even if, as the "Socratic method" many a law student has endured suggests, much of it often consists of Socrates asking questions and others answering things such as "It would seem so, Socrates."
Not in the Symposium though, where various characters (including the comic playwright Aristophanes) meet for a dinner party where all contribute to a conversation on the meaning of love--and I think even those derisive or fearful of something labeled "philosophy" would find themselves engaged--even charmed. Plato's Republic though, is likely the most famous of his works--even perhaps the most controversial. It has so many famous aspects--the question of whether one could be virtuous if you owned an invisibility ring and could cloak your crimes, and especially the "Allegory of the Cave," perhaps the most famous metaphor in all of philosophy. The Republic has taken heat for being the paradigm of the totalitarian state, as it posits an ideal state modeled after Sparta, where children are taken away from their parents to be raised communally and all aspects of the lives of citizens controlled.
Karl Popper has a fascinating critique of Plato along these lines in the first volume of his The Open Society. But he notes a contradiction looking at Plato's works as a whole. The Gorgias, for instance, which I studied in college, reads as a great defense of freedom of speech and expression. It's also not consistent with the three dialogues that tell of Socrates trial and death, The Apology, The Crito and The Phaedo. In the first Socrates defends himself as a gadfly--as someone that stings the lazy horse of the state awake--and who should be rewarded, not swatted. It's a spirited defense of the role of the dissenter. Popper attributes the inconsistencies to the differences between Socrates and Plato, as well as a change in Plato over time. In the earlier dialogues, particularly the more biographical ones about Socrates' trial and death, we get the genuine article. But more and more, Popper would argue, Plato put words into Socrates mouth that didn't accord with his democratic and libertarian beliefs, particularly as Plato grew more aristocratic and authoritarian. It is interesting in that regard, that in what is purported to be Plato's last dialogue, The Laws, Socrates disappears as a character altogether.
In any case, I'd strongly recommend becoming familiar with Plato--he's just as important to Western Civilization as The Bible, whether you're sympathetic to his arguments or not. (Indeed, much Christian theology is a amalgam of the New Testament and Greek philosophy.) At least try The Republic, The Symposium, and The Apology. And truly, reading the dialogues isn't arduous as is true of many philosophical tracts. The ideas can sometimes be difficult and sophisticated, but it's often a surprisingly lively read.
