This is a post just because I love maps.
This first link is to a pair of maps/graphs that show the distribution of the world's population by latitude and longitude. Only 10% of the population is south of the equator. Most of the population is between 20 degrees North and 40 degrees North. As for longitude, there are 4 distinct chunks to the data -- the Americas, which have under a billion people; Europe-Africa, with 2 billion; then a distinct valley before we get to the twin peaks of India and China that make up the Asia mountain with 4 billion people.
The second link is to latitude and longitude histograms showing the percent of land and water. Run your mouse over the charts to see the underlying world map. It is easy to see the big reason why most people live in north of the equator is that is where most of the land is.
That prompted the question of how does population density vary by latitude and longitude? Alas, I don't have the answer.