Plate and Counterflow Chillers
Counterflow chillers are a tube-inside-a-tube design and work by running hot wort from the boil kettle through the inner tube while cold water flows in the opposite direction through the outer tube. They are efficient and tend to minimize water use; they are the best method to chill large (10 gallons or more) volumes of wort. They also require diligent cleaning and sanitation, and work best with kettles that have spigots.
The classic CFC construction is coils of tubing, as with the Chillzilla.
Plate chillers use a manifold of stainless or copper plates instead of tubing, and this high surface-to-volume ratio makes them even more efficient.