Just a couple comments to BestBang4theBuck's post.

1. Silver and copper are actually more conductive than gold. Aluminum comes in fourth. Gold plating is used because gold does not develop a non-conductive (or poorly conductive) oxide coat (tarnish) as silver and copper do.

2. RF grounding conductors are hollow because of skin effect. As frequency increases, current is pushed to the outside of the conductor by self inductance. Since there's virtually no current flow in the interior of the conductor, it's cheaper (and much lighter) to make the conductor hollow. For a given cross sectional area, a flat plate has less inductance per unit length than a circular cross section and is easier to fabricate and install.