I voted for Shrek

The semis are between Antonioni's Alienation Trilogy, Polanski's Apartment Trilogy, Guy Maddin's Me Trilogy and Bunuel's Bourgeoisie trilogy, in the final it's probably down to Maddin vs Bunuel. Maddin would be horrified if anyone picked him over his idol, so my hands are tied.

The best trilogy is thus Le Charme discret de la bourgeoisie, Le Fantôme de la liberté and Cet obscur objet du désir. End of.