Indiana Jones and the Last Crusade: I think this one was my favourite of the lot. The story was well paced, with no silly detours, and very entertaining. It took everything that made Raiders great, and went that little bit further; for example, the schoolboy antics of Prof. Henry Jones (Sean Connery) and Dr. Brody (Denholm Elliott) added so much to their characters.
One thing I did notice, though: was the Roman numeral ten (i.e., X) missing from the close-up shot of the floor, when they show where Indiana's (Harrison Ford) broken it? It sure looked like it to me. Oh well, minor mistake if it was.