Avatar for me has to be the greatest cartoon ever..
Wife is re-watching it at the moment, and forgot how great it is..
It just has such a good solid adult story, with very serrious themes... but all wrapped up in a very kid-friendly stupid bundle.. Swear if you took away the stupid kid humour, but kept the plot-points/themes exactly the same, you could have a really solid adult drama.
100% on the list of things I want my future children to watch.. so many good lessons about coping with loss, moving forward, having balance in your life, respecting others, working together, and most of all redemption, that no one is one thing, and we have the ability to change.