Death Note is absolutely brilliant.
I've seen the final episode last weekend and I still can't get it out of my system. Well... Listening continuously to the soundtrack might have something to do with it, but I still fount it to be a near perfect story.
Death Note has several versions: there is the manga (Japanese comic book), the anime movies and the anime TV series. There is even a real live action movie released in 2006.
I've seen the anime TV series and I'm gonna give it a 10/10 for animation, directing and voice talents (for the original Japanese version, of course).
What I particularly liked about it is that there is no Good vs. Evil, no Light vs. Darkness. It's a conflict between two concepts. Let me put it simply: if you could kill every evil person on this world would you do it? Would you ignore a lifetime of believing that killing is bad and take upon yourself the role of the executioner? How would you decide who is evil and who isn't?
My answer is that I don't know. I believe there are some situations that you can't imagine a reaction for. You could say "I wouldn't do that", but in fact you can't give an honest answer because you're not actually in that situation. Furthermore, your answer is influenced by the person that raised the question; if you care what that person thinks of you, then you are bound to give an answer that will please that person.
You would think that answering this questions is a battle of mind and you wouldn't be too far from the plot of Death Note. The main character finds a note that enables the owner to kill just by writing down a name and he decides to purge the world from evil. But soon a mysterious investigator takes a particular interest in the case of serial killing. A duel begins between two brilliant minds, each trying to learn the name of the other.
The anime is a race that keeps you in constant tension. With each episode the situation changes and when you think someone is close to winning, a spin of events turns the edge to the other.
The characters are profound, unique and they evolve in response to the events that occur. Even more: there are no random events. You would even think that the characters defy fate and it's all about who can predict the other one's actions, who can control the environment and who can plan in advance. The tone of fantasy given by the Shinigami (Death Gods) and by the Death Note itself is fulfilling the plot in the unique way of Japanese stories. A bonus: there are no classical anime "teardrops" or "# signs" or "extreme big eyes" that you find in kids anime. I've seen the "small pupil" once or twice, but it was well placed and didn't bother.
The show has a slight fall after episode 25, once with a big event that steers the story on a different route. But even so, the second part of the series is worth watching as it concludes in a magnificent final episode that left me wondering what kind of person I really am.