I consider myself to be a newbie to Johnny's, and even till today I haven't heard every single band from JE.
But of those whom I have heard, here are the top three singers.
1. Domoto Tsuyoshi
The female half of Kinki Kids, eternal emo-boy Dots, also known as the Man who Cried after losing Janken.
2. Ohno Satoshi
In private, Arashi's leader been known to be introverted and gloomy. But when he opens his mouth to sing, you can hear sunshine in his voice.
3. Shibutani Subaru
Once rival only to Takki among the Johnny's juniors of the 90's, Baru has come into his own as one of the main vocals of Kanjani8.