One last note to this discussion that made the news rounds today. Is the U.S. Supreme Court about to lay the ground work so that you can't re-sell *anything* you buy? Could be. The appellate courts leading up to this decision have ruled that you should not be able to re-sell due to violation of copyright.
eBay has written a friend-of-the-court brief against such a decision citing that such a move would devastate U.S. commerce (specifically resulting in eBay practically going out of business).