in a book review in the nytimes, jim holt asserts flatly that ludwig wittgenstein was the greatest philosopher of the twentieth century. putting it mildly, i disagree. wittgenstein had a deeper commitment to conveying the fact that he was a genius than to any particular subject-matter or position. this, if you ask me, profoundly mars the work, which is characterized by a slipperiness edging into obscurantism: if the position lapsed into clarity, it would be refutable, and no longer readable as the expression of an intelligence transcending the merely human. the comparison i always make is to j.l. austin, whose positions are markedly similar to wittgenstein's, insofar as wittgenstein had any positions. austin is witty, clear, humble, and overwhelmingly original and smart. wittgenstein is overwhelmingly pretentious.
[on subject-matter: wittgenstein was obsessed by language, and had his role in centralizing language as the pre-eminent philosophical topic of the twentieth century. however, the same could be said of many of his predecessors and contemporaries: frege and w's mentor russell; peirce; heidegger; carnap/ayer; austin; and so on.]
now on the other hand, there are important insights in wittgenstein. one might point to the "private language argument" in the investigations, for example. and if holt had gone for "one of the greatest philosophers &c" i wouldn't have blinked, though i think even that exaggerates the achievement and underestimates the drawbacks.
of course, greatness is a self-fulfilling prophecy, and the unbelievably huge literature on wittgenstein, the status of texts in many subsequent debates, make him central whether you want him to be or not. but as with some other gnostic or oracular figures, there is a terribly unseemly cult of wittgenstein, acolytes muttering wittgensteinian incantations, followers who replace the world with wittgenstein's texts as what must be accurately reflected in order to speak the truth.