1. Jesus Christ
I am a Christian, but even if I weren't, I would still claim that Jesus Christ is one of the most important historical figures of all time. Through Jesus and Christianity, the morality and philosophy of Judaism gained a wider following, and became an integral part of western civilization. Several concepts of morality, such as reciprocity (the Golden Rule), non-aggression, and forgiveness, are immensely influential to this day due to Jesus' teachings and the widespread adoption of Christianity in a setting where previously the naked exercise of power was all the justification one needed for his actions. Christianity remains the religion with the most followers at the present day, making Jesus influential for that alone.
2. Napoleon Bonaparte
This man conquered most of Europe and implemented influential reforms in France, the most important of which was the adoption of the Napoleonic Code. The Napoleonic Wars reshaped the political landscape of Europe. French armies exported French revolutionary ideals, while at the same time the first waves of nationalism in many places erupted as a response to French occupation. Some countries, such as Venice, were wiped from the map, while others, such as the Netherlands, ended up as a monarchy. The French occupation of Spain led to the revolt of the Spanish colonies in the Americas. The Napoleonic wars revolutionized warfare, and show the first instances of countries mobilizing all their resources and people for the war effort. The legal legacy of the Napoleonic code is extensive, as it is the basis for many countries' codes. The code compiled centuries of French legal tradition based on Roman and German law, and may very well be Napoleon's most important and lasting achievement.
3. Nicolaus Copernicus
Since ancient times, most people rightly believed the earth was a sphere. What they got wrong was the belief that the earth was at the center of the universe. In ancient and medieval times, most "science" was not based upon empirical observations, but on philosophy. Copernicus, as one of the early figures in the Scientific Revolution, used astronomical observations and mathematics in order to develop his theory of heliocentrism, which has since been corroborated, with minor adjustments, by later observations. Copernicus not only introduced a theory which changed a widely-held fundamental view of the universe, but he also heralded the rise of modern science, which is based on empirical evidence rather than on cloistered philosophy.
4. James Watt
As the inventor of a practical and efficient steam engine, James Watt is responsible for the device which brought about industrialization, and, as a result, made a higher-than-subsistence living possible for most people in the world. The steam engine was used to power trains, which dramatically lowered transportation costs for both people and resources, and also indirectly created the modern concept of standardized time. The steam engine contributed to vast increases in the output of manufactured goods and mined resources, making mass production possible.
5. Johannes Gutenberg
Prior to Gutenberg, books were extraordinarily expensive, and only affordable by a small segment of the population. Johannes Gutenberg's invention, the printing press, allowed books to be mass-produced, rendering them cheaper and available to more people. Due to Gutenberg, literacy ceased to become a luxury, and common people were able to communicate and receive ideas received in printed material. The success of the Protestant Reformation, for example, was in part to the quick spread of Protestant literature. So widespread were books after this that states and churches found it necessary to ban works which threatened their authority, actions that were rarely taken in earlier times.