With all the focus on Rogue Squadron 3 on GC, I think its predecessor, RS2, deserves to be upheld as an example of the system's power as well. It ran 15 million polygons a second, (lower than RS3 but still a huge number) as well as pretty much every effect in RS3 minus light scattering. Bumpmapping on almost every surface, self-shadowed vehicles, tons of light sources, sharp textures, 60fps.
http://www.youtube.com/watch?v=RUFAS8pZr7Q
http://www.youtube.com/watch?v=IOGkAzO5tgM