Great post - Basically both attributes coexist and are much needed.
Rather that defining Leadership ; I want to focus on what a Leader does.
To be a Leader your have to lead, to have a vision, to see long term, to become egoless, forget about you and more importantly to develop others.
How do you become a Leader, you have to a Manager, to  lead you have to manage, to get things done, to teach others to develop others.
What is a Leader - A person that leads others and develops others into leaders, and also teaches (manages) others the how-to develop others into leaders.  A Leader creates a leadership factory.