My choice would be Death Note. This anime was, truly, a ride for me. The show is an incredible test. I would have disagreed with Light, even before I watched the series, but this series has brought be to considering things that I normally wouldn't, and learn new things about myself. It questions viewers, as to which side they are on, what they would do in the situation: what their outlook on "justice" would be. Overall, in a moral way. A big message in Death Note is how dangerous it can be, and how you shouldn't and don't have a right to try and play God, as human. I am certainly against "Kira". All humans are created equal, and we have no place and no right to choose who does and doesn't deserve to die, as Light tried to do, throughout the series. Killing is wrong, and he was a hypocrite for doing so, but what I just stated was MY main problem with his attempt at Kira. Light's understanding, I think, was that there was an equal amount of happiness and sadness in this world, and he wanted to eliminate the evil and create a world with only happiness. At first, he really did believe that what he was doing was good. "Kira" was an identity that the people came up with, themselves, and he basically decided that it was a good idea, and began striving towards that identity that was, at best, imaginary. And, eventually, he did loose himself to that identity, forgetting the Light that he could have been. He didn't become good or evil, in my opinion: I think Light became confused, more than anything. Obviously, he could not have done all of those things and become that way, unless it was inside him, all along, but there was still a happy life he could have had, and it's a shame he didn't resist the temptation to use the Death Note. What happened to him also shows the message: a human can't take the role of God, because that's not their rightful place. All that really did happen, was that anyone who got caught up in this "game" drowned in their own world of sorrow and tragedy. Light and L could have worked together and been the best of friends, as well as Mello and Near, and there is much more to it. Overall, I like how one can learn that rather than "fixing" and "helping" the world by trying to become God, the proper way is to love the true God.

Princess Mononoke it truly teaches us about coexisting with nature and it even doesn't pick sides in the war that goes on both sides are portrayed as good and just trying to survive. It gives you a respect for life.

Naruto/Naruto Shippuden. It teaches us many things... It teaches us that revenge just begets more revenge and unless someone has the power to forgive, the horrible cycle will just continue forever. It teaches us never to abandon a friend. It teaches us that it is better to have loved and lost than to never have loved at all.

At it's heart, Naruto/Naruto Shippuden is about friendship and never giving up. It is a touching anime and often moves me almost to tears.

Here are some quotes I thought would suit the forum:

'People live their lives bound by what they accept as correct and true. That's how they define "reality". But what does it mean to be "correct" or "true"? Merely vague concepts ... their "reality" may all be a mirage. Can we consider them to simply be living in their own world, shaped by their beliefs?' - Itachi Uchiha.

'When a person has something important they want to protect… that's when they can become truly strong.' - Haku.

'Those who can't acknowledge their real selves are bound to fail.' - Itachi Uchiha.

'Love breeds sacrifice… which breeds hatred… Then you can know pain.' - Nagato.

'It's almost unbearable, isn't it… the pain of being all alone. I know that feeling; I've been there, in that dark and lonely place, but now there are others, other people who mean a lot to me. I care more about them than I do myself, and I won't let anyone hurt them. That's why I'll never give up. I will stop you, even if I have to kill you! They saved me from myself. They rescued me from my loneliness. They were the first to accept me as who I am. They're my friends.' - Naruto Uzumaki.

Sorry I've got to post one more thing about Naruto...... It's just such a good anime.....

Naruto taught me never to give up even when the world doubts you and it is okay to be yourself. Gaara (as strange as this sounds) taught me to love and forgive. Itachi taught me to be devoted to what I do and the people I truly care for. Sai taught me that it is okay to have feelings. Sasuke has taught me so far that holding a grudge can only lead to loneliness and pain. Sakura taught me that growing up can be painful and you can’t love someone else until you love yourself. Jiraiya taught me the greatest thing you can leave behind is the people you taught, the ideas and skills are never lost. Hinata has taught me that hard work pays off and that it is okay to be shy but sometimes you have to be bold.

And the list can go on and on… sorry for the length of my corniness. haha

*looks above* welp..I was gonna post Naruto as well but you guys summed it up. xD
Wow I've cried so much because of Naruto, words cannot express how much I love this anime.
Like am I not the only one that cried when itachi left for the second time? ( I don't cry, that's how amazing Naruto is.)

An anime I that is my second favorite is Pandora Hearts, like wow there is so much put into one chapter of the anime/manga to the point where it'd leave you in shock. There is so much emotion to the point where I can't even sum it up, but this is what each character has taught me.
Oz: This character shows that everyone has the right to exist…
Alice: this character shows how a person can continue to live despite all the fear and problem anyone can encounter.
Gil: This character shows how loyal a person can be despite all the things that happened.
Break: This character shows that even though you have a terrible past you can still continue to live and be happy once again.
Sharon: This character shows how a woman can be strong despite all the challenges.
Jack: This character shows how love can be so powerful
Lacie: This character shows how a person can look at the world in such beautiful and pure way despite of being rejected by it
The will of abyss: this characters shows the people who feel being forgotten and being abandon all alone yet who can still stand up and faces the future….
Ada: This character shows that kindness and love can change someone.
Vincent: This character shows how can someone protect the person who is dearest to them..
Elliot: This character shows how honorable a person upon knowing his mistake and tries to correct it.
Leo: This character shows how a person can be a very loyal and caring friend

I could say so much more but I'm tired, but here's my favorite quote.
"Unbelievable... you are... just like... me... your very existence...made someone important suffer."