If Trump wins, he will be the first legally elected president since George W. Bush, and perhaps our reigning monarch, the greatest Republican, no the greatest person, in American history.
If he loses, he won't really have been the real representative of the current Republican party, just a pretender, an aberration. As such, Hillary Clinton's election will be illegitimate. She won't have really won an election. It isn't even clear, really, if a woman is allowed by the constitution to be president. Certainly not what the founders intended. We'll have to wait until the next president, or perhaps the one after that, before anyone new gets on the Supreme Court.
