The real Great Gatsby house on Long Island is on the market for a cool $3,888,888 (which actually seems like something of a deal coming from the Bay Area market prices). The movie version sure painted a Hollywood vision different from the reality of the beautiful (if not quite so sprawling) estate. I'd be tempted to restore some of it's original character (with modern conveniences still in place, of course). Check it out here.
(Realtor side note: The pictures are awful and do a real disservice to the property, as does the staging, or lack thereof.)