I have three.
Fight Club - This remains my favorite movie, not the best movie, just my favorite. That's one reason. Another Is how well Brad Pitt and Edward Norton fit their roles, and their chemistry and contrast. Everything else was great, the visuals, the plot. The film Is good enough on Its own.
Pulp Fiction - ... just don't, I don't care If fifty years down the road you want to update It, don't It's good enough.
Star Wars ( applies to IV, V, and VI ) - The movies are perfect. A product of talented artists, adversity, creative ideas, and the visions of a genius. In todays world the battle for Yavin IV would be populated with hundreds of X-Wings dropping the feeling of a scrambled last ditch fight, the battle between Luke and Vader would be coreagraphed, forgoing the tension of watching Luke battle a warrior more skilled them him, and the Ewoks will have celebrity voices, and will fully become useless. I fear deeply that If not George, someone will, ten years, twenty years, fifty years down the road.