Some of the most interesting layouts that stand out in my mind are those that are based on a historical theme such as the Pennsy in the 1940/50s done by Bob in Ohio, as well as those in other scales, such as the Key West extension, the coal fields of Kentucky and the Santa Fe in El Cajon area done by York.
Nearly all are, by their nature, selectively compressed and not a few are free-lanced in order to portray a representativeness of a particular region without coming under critical attack for inaccurate portrayal.
I have enjoyed an analogy between historical model train themes and historical fiction. Both must, by their very nature, be incisive and must include those dramatic elements that tell a great story, packed with emotion and discovery.