What do you think Julius Caesar's greatest battle is?
I personally would have to say that his last battle, Munda, is his greatest, with Alesia coming in a close second.
At Munda, Caesar himself said that he had fought for victory elsewhere, but at Munda, he fought for his life (too bad he was assasinated a year later ). At Munda, Caesar faced 80,000 Pompeiian troops of varying quality, with only 30,000 of his own troops. He had to fight uphill, and against another proven leader, Pompey the Great's son, Gnaeus Pompey. Unlike other victories like Thapsus, Caesar can be credited with inspiring his men through personal courage and leading them to victory. For much of the battle he was fighting alongside his crack 10th Legion. Finally, the victory was so complete, and the Pompeiians so scattered, that this victory won him the civil war.
In case this poll doesn't actually work, the choices I would give would be between Bibracte, Alesia, Pharsalus, Thapsus, and Munda.