This question is entirely a matter of personal opinion. Jon Krakauer claims to have tried to treat Chris as objectively as possible; he admits to personal bias and shows that Chris failed to properly prepare himself for the struggle of living in the wild. Krakauer notes in the introduction:
Some readers admired the boy immensely for his courage and noble ideals; others [thought] that he was a reckless idiot, a wacko, a narcissist who perished out of arrogance and stupidity -- and was undeserving of the considerable media attention he received.
(Krakauer, Into the Wild, Amazon.com)
Most opinions concerning Chris are based in judging his actions; was he correct to cut his family off from correspondence? Was he correct to refuse emotional connections with others? Was he correct to pit himself with little training and gear against the Alaskan wilderness? More importantly, were his goals and ideals worth the potential cost of his own life? Only Chris could have answered those questions, and only from a position of experience and hindsight; today, interpretations of his life are entirely subjective.
In the end, Chris made decisions and they cost him his life; his courage or stupidity (circumstantial stupidity, since he was very smart otherwise) is less important than the lessons the reader learns from reading about his life.