For Vertex Normal Interpolation, I import vertex normals from OBJ files, and use Barycentric Gouraud-style interpolation across the face of the imported triangle. The result is a very nice, smooth mesh rendering that is much more aesthetically pleasing and professional than the faceted look.

Venus De Milo mesh, no interpolation

Venus De Milo mesh with Vertex Normal Interpolation

Glass scene with no interpolation

Glass scene with Vertex Normal Interpolation