What is Greatness?

I guess greatness is tied in with success, and the many definitions of success vary widely. Some see success as an absolute, such as winning the Olympic sprints, while others see success as relative, such as a paralysed man walking the same distance. What is more difficult for Christians is that sometimes what we regard as success needs to be laid on the altar, so that God can do through our lives what He has in mind. That right now is my juggle. I long to do great things and achieve "greatness", but I feel the ever-present need to lay my life down and say like Jesus, "Not my will but Your will be done". What I expect in faith is this: as I conform to God's image, my ideas of greatness will change and I will do things for God that are indeed great, but not in the way I had originally imagined.