Spiritual civs have a strong chance to found an early religion, and their lack of anarchy lets them have a huge amount of flexibility when it comes to the civics (you can swap them almost non-stop as the situation dictates).
- Philosophical civs pump out Great People like no one's business.
- Industrious civs dominate on wonder-building.
- Creative civs get culture automatically in each city, so I usually play them aggressively early on, pushing out a lot of settlers and founding cities right on the borders of other civs, knowing that I can win the culture border wars thanks to my free culture.
- Aggressive civs are the best at fighting early wars; their Melee and Gunpowder units get a free Combat I promotion. That's a huge deal, not only because it adds +10% to overal strength, but because it opens up additional promotions (like Shock, Cover, etc.) and allows their units to get THREE promotions with just a barracks + Vassalage or Theocracy civics (Aztec Jags are downright scary - no resources required and very easy to get to three promotions early on).
- Expansive civs get free health, which basically means their cities can grow to larger sizes (and remember, population still = power in Civ4) not to mention they have half-cost granaries for early expansion.
- Organized starts out slowly, but the half cost civics really start to make a huge difference in the middle of the game, and saves a gigantic amount of money towards the end of the game. You can run the most expensive civics out there and barely feel it (also plays more of a role on the higher difficulties where civics costs hurt more).
- Financial gives you an extra commerce on any tile already producing two or more commerce. It's almost like having the Civ3 Colossus in every city! I'm sure you can see the advantages of that...
OK, let's look at the Government civics then. Hereditary Rule grants you happiness for each military unit in a city, WITHOUT LIMIT. You can grow your cities way beyond the usual happiness limit using this civic, or take advantage of a luxury-resource-poor start. Police State grants +25% extra production of military units AND -50% war weariness.Now Representation *WAS* the best civic for me, but that's because I was basing my strategy around heavy use of specialists to generate Great People, being Philosophical. If I had picked a Financial civ and gone the cottage route, Universal Suffrage would have started to look a lot more attractive. Keep that in mind