I wasn't aware of the importance of the Philebus in particular for the Italian Renaissance. From the introduction to Michael J.B. Allen's edition of Marsilio Ficino's commentary on the dialogue:
In 1462 Cosimo de' Medici granted Marsilio Ficino a villa at Careggi and put at his disposal a number of precious Greek manuscripts, including a complete manuscript of Plato. Afterwards two or three dialogues became especially dear to Ficino, among them the Philebus. Like the majority of the Platonic dialogues, the Philebus had been unavailable to the Latin west since antiquity, and it was Ficino who translated it from the Greek for the first time. More than this, he deliberately placed it in the climactic final position of the initial decade of dialogues he prepared for Cosimo's study. Cosimo and his friends discussed the decade culminating in the Philebus and these discussions informally constituted the inaugural meetings of the Florentine Academy. In 1464, as Cosimo lay dying in the last two weeks of July, it was the Philebus that was read to him; and during the reign of his successor, Piero, it was on the Philebus that Ficino first chose to lecture to the city's patricians, including the young Lorenzo. ...The first public articulation of Ficino's "direct acess" to the Plato text was a series of lectures he delivered on the Philebus, a series which later formed the basis of the written commentary. Consequently, the Philebus was in the vanguard of what was both a revival of an ancient academic philosophy, and also a wide-ranging religious, cultural and intellectual movement peculiar to the Renaissance and constituting one of its chief glories, Florentine Platonism.