Raiders for me because it's a perfect movie. It feels like it's the blueprint for every great action/adventure, sci fi, etc film that came after. Think about the things it does perfectly:
-action packed, Bond type intro
-brief yet impactful exposition scene, explaining the plot and stakes
-memorable introduction of side character
-multiple memorable villains AND nameless henchmen
-chase scene(s)
-"tables turn" scene where the good guy loses or is under extreme duress
-memorable ending "fight" (lol)
-memorable ending that leaves you wanting more
Star Wars, Terminator 2, Matrix, etc all follow the blueprint effectively. But I don't think any of them feel as brisk as Raiders. It blows by, no scene lasts too long.