My Physics teacher used to include a question about the speed of electrons in wires to catch people out, the speed of the Signal is close to the speed of light but the actual speed of the electrons moving in a conductor due to an EMF and neglecting small random movements is actually very low.
In a 1mm diameter conductor carrying 1 amp the average speed of electrons measured over a 1cm length of the conductor is in single figure mm/min.
There's lots of 'em in there (something like 8.4*10^22 electrons/cm^3) and current is a measure of the volume of electrons moving through the conductor,

 - Nick