The best 3D by far that I have seen was on the 3D version of Titanic.
It's a great movie anyway, and it already looked great, but it looks sensational in 3D.
You can pause the movie at almost any moment and get a fabulous 3D image. Whoever did the conversion put a huge amount of effort into it.
Kate Winslet and Leonardo DiCaprio, who looked pretty amazing in 2D, look even better in 3D.
Here's a still of the two of them as it would appear on a non-3D TV:
