[wbeaty]

The column of charge inside a metal wire is usually called "metallic electron-sea" or "sea of charge."

In other words, all metals are always full of electron-fluid. They're like plumbing pipes, but pipes which are pre-filled with water, with no bubbles allowed. During an electric current, it's the wires' own electrons which begin flowing. (A long thin column of copper is always a long thin column of movable electric charge. So, hook it in a circle, and that creates an invisible "electron flywheel.")

See the completed article: http://amasci.com/miscon/elect.html, a big list of common misconceptions.