Mannerheim - The first and only marshal of Finland. He rose to the rank of general of cavalry in the imperial Russian army before the revolution, after which he travelled back to Finland. In Finland he amongst other things lead the whites (non-communist side) in victory over the reds in the Finnish civil war. He also acted as regent for Finland after german prince who was king elect chose to reconsidr accepting the throne of Finland.
During the second world war he was commander-in-chief of the finnish forces, and managed to keep one if the most assymetric theathres (in terms of manpower and resources) in the second world war going. Afterwards he was president of Finland for some time. Mannerheim was accordingly instrumental in keeping Finland in the wester, non-communist sphere, keeping Finland independent and healing the wounds caused by the civil war. He is one of the few people decorated by all sides in both the first and second world wars.
Napoleon - Everyone know of his military genious, but for me having an impact on society as whole is as important as being a good general. I think we're all aware of Napoleons military genious, but for me his civil contributions are very important, if not more important. The fact that he was the patron of things such as the code Napoleon and metric system and reconcilling the good ideas of the revolution with the french society is what qualifies him as a great leader, whathever one thinks of him as a person.