I think the Volkswagen Beetle wins this contest hands down.
The reason is simple: the car was very well-built, extremely reliable and was unusually roomy for its day. That's why from the 1950's to late 1970's Beetles were everywhere
in Europe, and Beetles sold like the proverbial hotcakes anywhere in the world it was sold.
Today, a restored Beetle from the middle 1960's commands a lot of money.
I also liked the Beetle because my mom used to drive one when she lived in Hong Kong. Amazingly, that Beetle she drove is still around, recently completely restored to like-new condition in the hands of a family relative living in Hong Kong.