Since there's not one true answer and "standard" can mean different things in this context, I'll nominate another one...
@Chris1985's layout. Here's why I think it is a "standard"...
It encompasses almost every aspect of a what a train layout can be in a way that is attainable for many people. While not "professionally" designed or built, it displays a high degree of workmanship, and it's been done while he holds down a job. It contains many individual scenes, some of which are prototypical and some which are fanciful. He can run trains from a variety of eras. He uses all of the common types of control (well, there's no outside 3rd rail or dead rail... yet 
). It's big enough without being huge, and it's incorporated into what appears to be a fairly typical family home - no unusually large and/or custom built space. Apparently, his wife is on board with what he's doing. And he shares it with anyone who wants to watch on Youtube.
While we can find examples of layouts that are superior in specific aspects, I think that his layout has a high degree of excellence in a wide variety of the ways in which the toy train hobby can be expressed, and it's not intimidating for the average person.
