At the end of the novel Nick has had his illusions of the East Egg shattered, and when he sees Gatsby for the last time, he realizes that Gatsby is a more honest man than the others, despite his white lies, and tells him:
"They're a rotten crowd," I shouted across the lawn. "You're worth the whole damn bunch put together."
I've always been glad I said that. It was the only compliment I ever gave him, because I disapproved of him from beginning to end. First he nodded politely, and then his face broke into that radiant and understanding smile, as if we'd been in ecstatic cahoots on that fact all the time.
(Fitzgerald, The Great Gatsby, mrbye.com)
Nick comes to appreciate Gatsby's emotional purpose, his actions in pursuit of a clear goal, versus the shallow lives of the other residents in the East Egg. Even Nick's own cousin, Daisy, is barely able to muster an honest response to either Gatsby's declaration of love or to the accidental death of Myrtle. Nick can see that despite the pretensions of high-class by the East Egg, they are barely more than children with money, while Gatsby has worked hard for his goal, only to have it removed by jealousy and spite. Gatsby, therefore, is "worth the whole damn bunch" because of his inherent moral integrity.