I've steered clear of jewel thief and heist films as a rule, mostly because I feel like you know what's coming... the main variation will be the clever plot. As far as I can recall, I have broken this rule twice: once for Catherine Zeta Jones' dance through the laser beams in Entrapment, and now once for the sake of Peter Ustinov, with the 1964 film Topkapi.
I've always liked Ustinov, mostly because I was in love with the film Quo Vadis as a child, and he plays such a magnificently idiotic, tyrannical Nero that you can't ever forget him. On the other hand, I also once watched The Egyptian, of which I said to my parents that I wouldn't have believed that a film with Peter Ustinov in it could be so damn bad. Here, he plays a half English, half Egyptian lowlife con man who's sucked in by a pair of professional thieves to help with their plot to steal the sultan's knife with its four emeralds. He won a Best Supporting Oscar for this performance, which I think was probably due to the joy of seeing Ustinov play such a hapless loser... the scenes of him with his shirt off, getting the rope wrapped around for its later use in dangling a man down to the museum window, are a testament to what an actor without vanity will do for the sake of his art.
It's a nice enough film, though the sixties' colored lenses in the beginning will drive you temporarily insane. Maximilian Schell and Melina Mercouri, the pro thieves, have a crazy chemistry (playing a rigid Swiss and a self-dubbed nymphomaniac), and the shots of Istanbul are fascinating. But as with most heist films, you know what's coming... and it comes so terribly slowly that you might not hang in there for the actual heist. Hang. It is worth it in all its insane intricacy, and the end comes swiftly thereafter.