Another little thought I had regarding The Great Gatsby is the symbolic significance of Gatsby's house. Nick goes into the history of it at one point, talking about how it's designed to look like an old castle with turrets and such, and how the original designer offered to pay five years' worth of taxes on the surrounding properties if they agreed to thatch their roofs with straw (which they refused because, as Nick said, Americans don't take to being peasantry).
Given that this was written during the 1920s, which was the time of Art Deco and Bauhaus modernism, I feel that this is very telling. The design and history of the house is representative of the absurd archaism of the upper classes - the way they clutch at the past and pretend at being nobility when the time for nobles has long since passed.
The fact that this is the house that Gatsby buys is in itself metaphorical, of course, but so is the lifestyle he operates out of it. His famous parties which everyone in the city attends are a closed world to Daisy, full of life and opportunity, the height of Jazz Age culture. Gatsby doesn't belong in the world he tries to occupy - but that is a credit to him.