My favorites are: Singer 15-91, Singer 201, Singer featherweight, Singer Red Eye (model 66). A close second goes to my late 70s Kenmore, which I bought new, a 1902 Singer 27 treadle, and a 1957 mauve/pink Kenmore 158.351. All of my machines are in good working order, with the exception of a 1930s Singer 101 and an age unknown White Rotary which started life as a treadle and was later electrified.