Great idea for a thread Arnold!
Some great current layouts have already been mentioned. Being a Pennsy fan myself, I agree with the term “standard” for both the prototype and the layouts mentioned. That said, my nomination goes to the late great John Armstrong’s Canandaigua Southern. He was an innovator in so many ways. I particularly liked his unique steam locomotives and his layout name resonated with me as I grew up in nearby Rochester NY.
As a runner up, I think the South Shasta Lines was magnificent. I drooled over that layout in the pages of MR as a kid, but I do not remember the builder. Can someone help with that? Any idea what happened to that layout?