Tsk, tsk.
Don't forget that it also shields against stray electrical fields...
The following taken from my physics textbook:
In an insulated conductor carrying charge Q, charges will move until the resultant force on them, and hence field intensity, is zero.
Now consider the Gaussian surface, just inside the surface of the conductor. Field intensity is zero, hence flux is zero. Gauss's Law tells us that flux is equal to charge divided by permittivity.
If flux is zero, this means that charge is equal to zero. Hence, all charge on an insulated conductor resides on its surface. So, similarly, the field is zero at every point inside an empty hollow conductor.
Obviously, as well as charge residing on the surface, electric current also moves across the surface of the conductor.
Which is why we get electricity board guys in these funky conductive suits, pieces of static-sensitive computer equipment inside little bags with a conductive mesh in them (I think) and co-axial cable.