One thing to keep in mind: if you constantly expand, and do it in such a way as to maximize trade, you can use luxuries to keep people happy and productive. Luxuries work in Monarchy and Despotism, not very well, by they work. I use a tech edge to expand by relaxing the Science rate and using the extra income to make folks happy. The expansion then reciprocates by creating more trade, thereby more science(and tax, and luxury). In my current game I probably have 40+ cities, and with all the good wonders keeping them happy, a mere 30% Luxury rate is keeping most of them celebrating WTLPD. I'm getting a tech every 4 turns, and about 350gp/turn. The chinese have a relatively tiny empire, with nine cities, all huge, and two they conquered from the barbarians which are miniscule. I intend to relieve them of the burden of those cities soon, and then I'll give their leader an early retirement option that he'll have no choice but to accept. The other civs mean squat. I'm gonna conquer the entire planet, build a huge army, and then go smear the AC civ. (ToT)
