Obviously, this question is a matter of opinion and can have a variety of responses. Ambition is defined as a strong desire to achieve something despite the obstacles placed in your way. It would be hard for anybody to argue that ambitious would not be a good word to describe Julius Caesar.
Caesar was born of the patrician class but was not among the most wealthy in Rome. He ambitiously rose through the political ranks utilizing negotiation and political savvy. His ambition as a military general led to the expansion of the territory of Rome, with the victory over Gauls as the hallmark achievement. His socio-political reforms, namely land redistribution for the poor made him incredibly popular with the plebeians. In the end, his ambition became his worst attribute. After declaring himself dictator for life, Caesar was assassinated by members of the Senate, who felt his ambition was a threat to the Republic.