There are tons that I've replayed at least once, but the ones I've replayed the most are probably Final Fantasy VIII, IX and X, The Legend of Dragoon, Mega Man 2 and 4, the first three Uncharted games, and Shadow of the Colossus. There are others that I might have only finished once or twice, but which I've otherwise played a lot over the years, like Super Mario Bros 1, 3 and 64.