I love the Nikon F (and the 105mm). It's also a great 1960's icon.
It used to be my absolute favorite, though now, IMHO, there are even better classic cameras with much better viewfinders (and even better lenses than the 105).
As far as Grandads go, I'd also propose Pentax, though Praktina, with its motor drives and 250 frame backs was, in part, even more innovative.
About 1950's lenses, I'd say Zeiss was usually better than Leica (and, according to tastes, today is about its equal).
Other truly excellent lenses were being made by Zeiss Jena, Angenieux, Steinheil, Voigtländer and many others.
Yes, the Nikon F is definitely something to be happy and get excited about, but some perspective should be kept...