Materialism is a powerful element in Fitzgerald's work. I think that the obsession about wealth and its trappings proves to be emotionally destructive for Gatsby and the "flapper society" in which much of the novel is depicted. The idea of materialism becoming an element that automatically indicates value is something that is brought out and criticized in the novel. Additionally, Gatsby believes that wealth is element that will allow Daisy to fall in love with him. I think that the basic premise of being able to substitute love and affection with the acquisition of wealth is another comment on materialism and its presence in the time period.
Granted, many of the characters, notably Gatsby's party guests, are materialistic and social leeches. There is also the idea that the end justifies the means. Gatsby goes to any lengths to pursue Daisy, his "American Dream." It doesn't matter to him, that pursuing this dream entails changing his persona (which in different contexts is not necessarily bad), getting involved with criminals and hosting parties for a bunch of phonies. The deaths that occur in the novel, although not intentional are the result of this mix between Gatsby's pursuit, Tom's infidelity and some poor driving; all of which, even the last one, applicable today. People want what they want and in materialistic societies, they want it NOW. But back to my overall point: Gatsby's "end justifies the means." Think about these reality shows like "Survivor" and others like it. They are Machiavellian. Each participant will do whatever it takes to win; usually money. Likewise with Gatsby. This concept of the American Dream trumping all other considerations of other people is definitely noticeable today. This actually comes from a (not to play politics, but) predominantly republican view of capitalism where competition is the guiding hand. The problem with believing this view absolutely (believing only in this view) is that it ignores social factors which clearly show that competition, in and of itself, is an fallible guide for life. Strict adherence to competition alone ignores social inequalities, economic infrastructures and subsequently, ethical considerations. Characters on these reality shows are in it to win it, no matter who they step on. Sadly, this can be the price of success: the end justifies the means. However, a more tragic end for Gatsby. Still, Nick presents Gatsby in a more favorable light. At least Gatsby's in it for love.
We are still an incredibly materialist society, just like the 1920s one that Fitzgerald criticized. Consider all of the things that we buy, the size of our houses, the balances we carry on credit cards. It's gotten slightly better during the recession, but we are still much more materialist than most other societies.
We are also quite insulated, just like the characters in the book, from outside events in both the country and the world, living as though there is no tomorrow or no need to worry about one.