Probably Venice or Rhodes. For Venice just park a stack in front of the town and anyone attacking you gets your city garrison as a free bonus to fight. Good income and access to the eastern waters. Besides, its probably the best place to use as capital once you got most of the world.
Rhodes. Its an island and you can place single peasant units all across the landmass to prevent a land invasion. Not good economically but can be used to train units for warring the lands around it.
Bookmarks