Superman - The Movie (1978)
Beautiful! However, if you buy it as one of your very first Blu-Ray discs, you may be confused about the picture.
While the colors are vivid, the picutre seems a little 'soft', and that was how Richard Donner made the film. It almost has a dreamy quality to it.
That being said, you can now drink in all sorts of little details that you may have missed the first time. My favourite is that you can see that among all of Lex Luthor's new mapped-out Californian cities are a pair of large mountains called "Tessmacher Peaks".