One of the things I admire about President Bush was his willingness to face evil in the eye and name it for what it is. "Evildoers" sounds like a comic book word, but the people who attacked America last year were not sick, misunderstood, or disenfranchised: they were evil.
Ravi Zacharias says in answer to the problem of evil in the world that we must first address the evil within ourselves. Like Luke Skywalker in Return of the Jedi, we must take a stand and refuse to become like the evil people who cause so much pain and misery in the world. Luke chose to admire his father for the good man he had been, and refused to take part in the evil his father had come to represent. I think it's important to have heroes, people of character and selflessness we can admire and imitate, as well as repudiating the evil we see.
The Christian standard is to allow anger, but refuse to use that anger as an excuse for sin. I will not let the hurt and pain rising from the evil events of a year ago drive me to become like those who caused them.