My favourite is the The Professor (プロフェッサー, Purofessā) Hiruzen Sarutobi for being so loving and caring.
NarutoWiki: Due to the long life he had lived, Hiruzen served as a source of wisdom for much of the series, passing on the things he had learned to the next generation. As Hokage, he had also acquired a habit of attempting to end things peacefully, and did what he could to avoid bloodshed amongst his allies and his enemies. At the series' start, Hiruzen was one of the few people who saw Naruto as more than the container of Kurama, and, as such, became someone that Naruto truly admired, even thinking of Hiruzen as a grandfather-figure.
According to Kakashi Hatake, Hiruzen loved his students deeply, including Orochimaru, no matter how far he had fallen. This ideal stems from his belief that Konoha's next generation is a precious resource that must be protected.
Hiruzen was also bit lecherous as well, as he enjoyed spending much of his free time talking to young girls, which was his favourite pastime, and when Jiraiya was still his student, he offered to help Jiraiya test the technique that would allow the user to spy on naked women unnoticed. Even Jiraiya, in this instance, noted his sensei's perverted qualities. He also fell victim to Naruto's Sexy Technique on more than one occasion, fainting after he saw it.