Urameshi Yuusuke I am not sure how to classify Yuusuke. At first, he's your average school drop out without a future, but then, it's strange because he's not exactly that, as the typical stereotype are usually insensitive and complete loners, who have really crap phrases to say. Let me assure that this is NOT the case.
Urameshi Yuusuke, although doesn't have many friends in the beginning has an 'attachment' to Keiko. His long time rival Kazuma Kuwabara, as usual in all types of anime, becomes one of his best friends after his reincarnation, and all of Yuusuke's friends extremely value each other's friendship. They value enough to be willing to die for each other.
Although such friendship lines are often in many other anime, there is a way that Yu Yu Hakusho does it which makes it a level above the rest. I think Yuusuke is the source of the best group of friends ever.