All time: Dr. Martin Luther King Currently living: Bill Cosby. Not a lot of people know this but he grew up a poor kid in the projects. He took his education seriously and used it to rise above his circumstances. Today he spreads the message of the importance of education to young people, particularly the under-privileged.
There is a gentleman who is 94 that lives down the road from me. We all fight about who gets to mow his lawn, weed the flowers and help with his garden. After you help he has you come sit down and while you drink his homemade lemonade (the best I have ever tasted) he talks and tells about his life. I have learned so much from him. In my section of the world he has changed all of us for the better.