A correction in today's New York Times addresses the question of who said "It is the journey, not the arrival, that matters":
An article on July 20 about the economy's effects on Americans' vacations misattributed the saying that it is the journey, not the arrival, that matters. Although it has been attributed through the years to T. S. Eliot — as the article did — Leonard Woolf, the author and the husband of Virginia Woolf, in his autobiography, "Downhill All the Way," cites Montaigne, the 16th-century essayist, as having written, "It is not the arrival, but the journey which matters."The Times did better than me (as well it should, right?) by tracking down the work in which Woolf attributes the statement to Montaigne (I just confirmed it via Google Book Search). The correction makes no reference to Woolf's own The Journey Not the Arrival Matters and (perhaps wisely) avoids the question of whether Montaigne is the source of this aphorism.
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From Eliot to Woolf to Montaigne