Use a Phong shader to produce glossy plastic-looking sufaces. Phong shaders are good for modeling things like car and bathroom mouldings, and many high-tech polymers and plastics.
Use a Lambert shader to produce a surface that appears flat, with no reflections or highlights on it. Lambert shaders are good for modeling things like chalk, matte paint, and other unpolished surfaces.
s a material (shader) that is particularly effective at simulating metallic surfaces (for example, brass or aluminum) which typically have soft specular highlights.
Use a PhongE shader to produce glossy surfaces. PhongE is perfect for creating plastics, or the kinds of polymers used to create bathroom and car mouldings.