Tree-lined broad avenues, the smell of sweet olive bushes, Victorian style homes, modest shotgun doubles loaded with ginger-bread, and two of our universities are but some of the features which justify the prices of real estate in the Uptown and Garden Districts.  Did I forget to mention Audubon Park with its magnificent golf course and Zoo?  Those who live on Exposition Boulevard are entertained nightly with the sounds of the zoo animals.  How many metropolitan areas can offer that boast.    What was once five separate plantations is now a premier address in New Orleans, its development courtesy of the New Orleans and Carrolton Railroad which made the 5.2 mile trip from Baronne and Poydras at the speed of 1 mile per hour, not bad for the early part of the 19th century.   Now those plantations have become mansions, more modest homes, condos, rental apartments, and some unique retail areas.  Even more than the famous French Quarter, this is a memory tourists take home.