I chose Sam as the greatest hero in The Two Towers. Despite his grief at Frodo's (apparent) death and his fear of the task ahead and his innate humility, he takes the Ring and resolves to complete the quest, alone. That took tremendous courage.

I chose Saruman as the greatest villain. He betrayed not only the good guys, but also Sauron, in trying to obtain the Ring for himself. He wantonly destroyed anything and anyone in his way. He employed orcs and even bred his own. Even in defeat, he never stopped scheming. In book 1, he displayed scorn for Gandalf (and Radagast) but after the fall of Isengard he doesn't hesitate to try to flatter and seduce Gandalf to his way of thinking. And he has the nerve to try to characterize his attack on Rohan as some kind of misunderstanding. Sauron never pretends he is anything but a conqueror; Saruman is the worst kind of two-faced evil weasel.