what is the significance of the novels title? is gatsby truly "Great?' Nick tells him that he's "worth the whole damn bunch put together." is this true?

Gatsby has the greatest quality in that his love of Daisy, while somewhat misguided, is the center of his life.  He actually takes the blame for Daisy's accident and is willing, literally, to take the bullet for her error.  In one sense, giving one's life for someone else is the true greatness as many people would define it.  Nick recognizes that many of the people in Tom and Daisy Buchanan's social circle are frivolous and superficial. While it is true that Gatsby has done some illegal things in his life, he has had some innocent motivation in his love for Daisy.

This happens in Chapter 8. Gatsby and Nick have a long talk about Gatsby's past. Gatsby confides that initially he just wanted a bit of action with Daisy but fell in love. From then on he never felt worthy of her because of her high social status. This sickens Nick because he hates these vacuous ultra-rich people. He thinks Gatsby is worth more than all of them together (hence the quote). Nick laments that Gatsby is pining away for the shallow Daisy when he could be making more money and throwing lavish parties. Nick loved the old Gatsby from the beginning of the novel. He liked the mysterious paradoxical counter-culture that Gatsby represented. He does not like the more human Gatsby showing his frailties and desires. Nick sees two sides of Gatsby. He sees the dreamer and he sees the conformer. Nick adores the dreamer Gatsby. He likes his sense of hope and magic even amidst of the superficial socialites of East Egg. Nick loathes these people for their self-absorption and inability to feal anything real. Nick shouts out, "You´re worth the whole damn bunch put together." He says this as if to remind Gatsby that he (Gatsby) was never like the socialites and they don't deserve him.