Why is Rome #7?
Rome has been one of my favorite civilizations to play as since the first game of the series and this preference has more to do with their iconic status as one of the World's most powerful and aesthetically glorious empires than with any in-game features. Indeed, what you get isn't all that exciting, although I do enjoy building roads with Legions and the Ballista is a slightly better version of a unit I never use. The unique ability is what would be considered boring but practical, giving a production bonus to satellite cities on any building in Rome itself. Just use gold to quickly buy a new science building when the relevant technology is gained, for example, and then get it cheaper everywhere else. That's not too bad actually, but it's a subtle effect compared to some of the other abilities. Rome is mainly in this spot because of my arbitrary personal preferences, but that's the best reason there could ever be, right?
Caesar: scheming and powerful yet full of human frailty.
It was one of the first times I went Liberty instead of Tradition and I was actually able to settle six cities before direct violence became the only way to expand further. The Glory of Rome bonus was hitting on all cylinders in cranking buildings and the bland successors to the unused unique units took out the rest of the continent. I got the Order ideology first and became ridiculously strong but decided to stay out of the affairs of the other continent whose nations regarded me as a peaceful trade partner without wondering why half of my cities had French or Aztec names. Then it was just a matter of choosing the victory condition, ultimately settling on building a spaceship. Ad astra per aspera.
Remember when the Civilization games actually had a senate that overruled your wars?