For an actual green surface I'd have to pick PVGC's #2, as some others on here have.
I never gave it all that much thought but I doubt it would be half the green it is if it was not so raised. It's perhaps the longest functional approach shot relative to its actual distance I've ever seen or played (ironically with perhaps the single exception of its copy hole green on PV's Short Course).
The fact that it's just sitting way up there looking straight at you from the tee is very cool too.
This green and green site is probably an example of how luck shines on some golf holes.
There's no question at all that Harry Colt proposed that the green on #2 be sited and built off to the left and perhaps a bit lower than the actual hole. And he proposed siting the tee for #3 precisely in the middle of what is now the 2nd green.
Crump apparently overrode this idea with his famous remark to his friends of "NO GOOD" to Colt's idea. At that point Crump may've just become somewhat proprietary about what he had already routing and probably "roughed in" for this hole.
But there is something that I've never reported before about this green that certainly is interesting and will probably always remain mysterious as to whose idea it was or who drew it because either above the drawing of this hole in Colt's hole-by-hole booklet or perhaps on the back of the page there is a pencil doodle that looks sort of like a rolling W.
There's no question in my mind that this was a doodle for or from the idea of the amazing in-line double swale feature of this remarkable green.