I'd have to go with Raiders for the no.1 spot! Raiders is just really a perfect movie, great characters, great villains, adventure,drama, romance, comedy,suspense you have it all. And amazing score, but what else would you expect from the legendary John Williams,and awesome special effects from the wizards of ILM. There is a reason Raiders is considered one of the greatest films of all time by the A.F.I. and countless critics all over the world. It brought us Indiana Jones, the greatest screen hero in motion picture history!
As a side note I did want to give honorable mention to TOD, which I think is highly underrated! Yeah it's dark and Spielberg hates it now, but I loved it as a kid and still love it! Indy was a real bad@$$ in Temple, not that he wasn't in the others but he had a slightly diff. edge to him. The opening scene is terrific in his James Bond Goldfinger tux, the fight w/the giant thuggee and then all the other guards, the mine car chase, the bridge scene, and let's not forget John Williams score. The scene where Indy frees the children of the village, and
shows up in the tunnel entrance w/the light pouring in from behind, and then you here the punches and the guy goes sliding across, is one of the best scenes in the series to me!