The answer to this question is going to be largely up to personal opinion and preference.
In my opinion, Atticus' closing arguments in the trial scene is far superior in the movie compared to the book. Gregory Peck nailed that role. Even when I read it today, I hear Peck's voice as Atticus, speaking with the same conviction. To me, this is a scene that is as moving as the coach's final speech in "Hoosiers." If I was a lawyer, this would be a scene I might watch to pump myself up for a trial.