2 that come to mind. A Norton. I think for me it's the openness of the frame around the engine. The forward cant of the cylinders. The polished valve covers. The exhaust pipe shape and sweep are so classic it's copied on many other bikes. How many others have you seen with the famouse Norton pea-shooters on them. the whole package just works so well. In my eye a Triumph or BSA just doesn't have the same appeal. The only other bike that really works for me are Guzzi's. Primarily just for the motor. There is no doubt that a Guzzi constantly lets you know it's a MOTORcycle. From a side view it there big as life, from the front as well as the back you can see those cylinders out there. From the top when your riding with your knees right up by those heads and crouched down with hands on the clip ons, they're right there. Especially the first Lemans or V7sports. They are so long and low, like a missile, the Mandello missile. They just look right. Others look nice but those 2 have to be at the top of the list. What others would a general concensus reveal as the best of the best. A Goldstar clubman single? Vincents are nice but look kind of busy.