One of the unfair truths about the real estate market is that the most expensive neighborhoods are the ones that tend to rise the fastest when times are good -- and are also the ones that hold onto their value the best when times are bad.

So, even as prices plummet in places like Las Vegas and Orlando, FL, you will likely do better in the long run with your real estate dollar if you buy a home in an expensive neighborhood that is currently retaining its home price values.

To see just what you would pay for a home in one of America's most expensive neighborhood, Luxist asked NeighborhoodScout, a research firm with a huge database of neighborhood statistics, to provide a list of the most expensive neighborhoods around the country by zip code.

Dr. Andrew Schiller, a geographer and founder and president of NeighborhoodScout, did this research. His initial study found that many of the priciest zip codes are clustered within 30 miles of Los Angeles and Manhattan. "Around the biggest cities, there is a lot of demand and the greatest opportunities for people to make money," he explains. He notes these neighborhoods also tend to have great schools, wonderful views, nearby outdoor recreation and other amenities.

So as not to have our whole list made up of homes on either coast, we asked Schiller to include zip codes in all quadrants of the U.S. That explains why we include some of the most expensive zip codes in the Mid West, even though they are actually less expensive than quite a number of other zip codes found around the cities on either coast that we didn't include on our list. The result is a geographically diverse list of the 30 most expensive zip codes.

Luxist editor Deidre Woollard supplemented the research by identifying a property for sale and including it as the Estate of the Day.

If you are real estate shopping today and worried that prices could fall further across the country, buying in one of the most expensive zip codes in your region could be a smart strategy. "There is no doubt," says Schiller, "they do hold their value."