I divide my taste into visual appeal and practical. Everyone loves to look at a big fat cock but in practice...
For visual appeal it's never about the length honestly, but girth on the other hand- that is only thing that matters really.
For practical usage? Anything above 13 cm (5.1 inches) - 17 cm (6.6 inches) is golden. Anything above just starts poking all the unnecessary places and doesn't bring a pleasant experience. Girth on the other hand, 4 cm (1.5 inches) - 6 cm ( 3 inches) is good, 6 cms is already pushing it. I'm on the tighter end so fat cocks either hurt or just feel like nothing because I'm continuesly trying to loosen up.
Slight bumps on a cock are nice in practice, depending on the severity of it, but a little girth increase in a small area feels really good.