> I realize that this is a bit late as this thread is quite old and worn out by now, but I just thought to say that by Sam's logic, bacon is not a topping either.

By my logic, bacon is a topping depending on the circumstances, just as cheese is. As I've said before, cheese is a hamburger topping but not a cheeseburger topping. Bacon is a cheeseburger topping. Bacon is a hamburger topping. Bacon is not a bacon burger topping.