A documentary I recently watched indicated that man settled once he began grinding grains. Simply put, carrying all those heavy stones around was too much trouble. So, even though man was still a hunter gatherer for thousands of years after forming permanent settlements, the basics of civilization began once carrying all their stuff became too burdensome.
In history we have the following:
Africa/Middle East:
Egyptians began setting in communities as far back as 10,000 BC, originally doing so in desert oasis areas. Obviously, that makes sense. Also, inbreeding was avoided by slave trade and intermarriages with the various desert nomads. Eventually this band moved into the Nile Valley, apparently after climate change forced them out of their desert haven.
Americas:
South:Andean civilizations began along the coast of Peru roughly 3500 BC. Like the Egyptians, the Norte Chico overcame living in an arid region by settling in a river valley; earliest settlements date back to 9000 BC. Unlike Egypt, which relied on one river, the valley settled by the Chico people was one of many rivers, all of them draining the Andes.
Central: Pre-Olmec early farming cultures date back to 5000 BC. Multiple civilizations in that region followed shortly thereafter, culminating in the Aztec, which were finally destroyed by the Spanish.
North: The Folsom complex found in Wyoming seems to indicate hard, standing dwellings which date back to 9000 BC, which brings up another reason to settle: get out of the weather with permanent structures that resist wind, rain and cold.