A good leader leads others with a motive driven by correct moral values. A great leader is someone who has the ability to lead others and motivate them to do something, regardless of his motive.
Take for example, Hitler motivated the Germans to fight and take revenge against the 'allies', who defeated them during the World War 1. His motive is to take revenge and to wipe out the Jews.
World War 2 has killed many innocent people, separate many families and it is appparent that Hitler's motive of starting this war is wrong.
However, we must admit that Hitler had been a great leader. Although his motives were not right, it is true that he managed to motivate and lead the people to success when they are all very discouraged and depressed after the World War 1.
Singapore has many both good and great leaders. The most prominent one being Lee Kuan Yew.
He has confidence - the value that made people respect and trust in his decisions.
He persisted in his decisions and actions no matter how many opposed it. When he decided to construct the MRT system, many opposed it, insisting that Singapore was very small and there was no need for MRT system and that Lee Kuan Yew was just copying the other countries.
Now, people praise the MRT system, saying that it brings tremendous convenience to the people to go to school and work, providing a fast, cheap mode of transportation around the whole island. Lee Kuan Yew definitely had extraodinary vision and foresight, did not listen to other's complaints and carried on with confidence his plan, because he knew it will one day benefit the people.
There are too many good and great leaders and I shall not list them all.