Alpha Centauri is clearly the best of all the Civilisation games. Although not a direct sequel, it does carry on past Civilisation, representing the events that occur when the ship you launch to Alpha Centauri arrives. I encourage all of you to play it, especially if you appreciate really, really good writing. Various ideologies and the effects of future technologies have on civilisation are all presented in entertaining and cool ways.
Thought I'd write something somewhat intelligent for a change.