I'm in complete agreement with a post Prof. Ken Blanchard made today on the South Dakota Politics blog.
I agree with him that Severus Snape, from the Harry Potter books, is not evil. Like Blanchard said, Snape is a "son of a bitch." And he has no problem abusing his position to get revenge for all the pain Harry's dad caused him in the past. But while he may be a jerk, that doesn't make him evil.
A reoccurring theme throughout the books is that whenever something bad happens at Hogwarts, Harry and his friends always assume Snape was involved. They were always proven incorrect, but that was all set up for the end of the sixth book. Now it appears that Snape truly has gone to the dark side. But has he really?
Blanchard also talks about Dumbledore's pleading with Snape. But he wasn't pleading with Snape to spare him. He was pleading for him to do something. What was that something? Maybe he was supposed to spare Draco Malfoy from becoming a murderer? Maybe it's about something that hasn't happened yet? Whatever it is, we'll find out in Book 7 next month.