The penny is Abraham Lincoln. The $100 will is Benjamin Franklin. The penny may be worthless, but it is also the most common and the most people know whose face is on the penny, because everyone can afford to look at it every time they get change or reach in their pocket. Thus, the penny image certainly has the most publicity and widespread knowledge. The $100 is the most valuable bill, but likewise it is the rarest. More people know who is on the $100 because of phrases like "benjamins"; but if your face was on it there is no guarantee that a special phrase using your name will be use to describe a $100 bill. So there are benefits to both. Which would you prefer?