Yoda
Obi-Wan
Qui-Gon
These names all capture the Mentor's Spirit. They are wise teachers that show that good comes from helping others. Heroic and self sacrificing, they are, for the greater good.
If we delve into the EU comics I would have to mention Zayne, Cade, Dass Jennir, Wolf Sazen, Quinlan Vos and Aayla Secura. All of them have been enlightening on the many different perspectives a Jedi can have.