Best? Always arguable, but a good case can be made for the MONē.

The Czech-manufactured Velosteel is a modern build of the old roller-actuated Fichtel&Sachs. A bit hard to come by in the USA these days.

I'm fond of the Sturmey-Archer S1C with its anodized alloy hubshell:




Fun fact: in 1908, a rider set a new record on the ~900 mile Lands End to John o'Groats open road course riding a bike equipped with a Sturmey-Archer coaster hub. This record stood for 20 years!