Enthalpy701:
edit: Apparently the basic linear regulator is zener based as well: http://upload.wikimedia.org/wikipedia/commons/9/92/Zener_reg.gif Linear regulator - Wikipedia
That may be, but that circuit is not the equivalent of a 78xx linear regulator, it just illustrates using a Zener as a simple regulator. A 78xx has several important advantages over that circuit.