I've thought this before but upon re-watching last night it really affirmed it. In terms of visuals alone, the most beautiful-looking film I've ever seen is Titan AE. I love animation generally but it's just something else. It's the most amazingly colourful film I've ever seen and certain scenes such as the water planet with the hydrogen trees, and the ice rings at the end (and their homage to Enter The Dragon's mirrors) are just incredible. Favourite moment (although it's cheesy) has to be the ship bursting through the nebula with the "wake angels" spinning around the front. It's just gorgeous. Not many seem to have seen it but it's well worth checking out.