west egg and east egg
Well, since Gatsby takes place a few miles from where I live, I can give the historical perspective. East Egg and West Egg supposedly stand in for the real towns of Great Neck and Little Neck/Douglaston. Great Neck was where all the parties were in the 20's (the skater Sarah Hughes is from there). However, the valley of ashes is the old grounds of Flushing Meadows-Corona Park, which is just a few blocks away from where I live right now (in Rego Park). And, the valley of ashes is not actually between Great Neck and Little Neck. In fact it's many miles away from both of them. So, I think this kind of destroys that specific theory, but it sounds good anyway, despite the facts.