No votes for the Iroquois yet?
I'll second a vote for the Iroquois!
My current game is the first time I've played the Iroquois (random civ - otherwise, I had not considered playing them before). Three reasons:
1. Argiculture is probably the best civ trait in the game.
2. I think the Mounted Warrior is among the top 3 units of the ancient age - the Ancient Calvary & Gallic Swordsman being the others (yes, I did left out the Immortals, but I'm talking about my top 3 not my top 5
). Speed kills.
3. The Commercial trait is underrated by many players. I consider it the second best civ trait in the game. It allows for a higher OCN thus a bigger empire and lower corruption - meaning more shields and gold in almost every cities.
For example, in my current game, I have an island city/base named "Vice City" that "orbits" another continent a hemisphere away from my empire (game settings - huge map, 16 civs). Vice City is by far, the farthest city in my empire - but will be an important base of operations for my eventual invasion of this continent (I've been eyeing their luxuries... muhahaha
). As a 4-tile island, it doesn't have a lot of shield potential - and besides, I irrigated the land anyway - but if there were no corruption, it could generated 6 shields. But as a remote territory, 3 of the shields are lost to corruption...
Think about that for a minute: A 3-shield producing city far, far away from your empire! Note: Vice City does have a courthouse but no police station.
Industrious civs may get one extra shield in each city, but commercial civs may save 1-2 extra shields and gold from corruption in every city, and as a cherry on top, gets an extra gold in every city too. This trait doesn't get any discounted buildings, but it will allow you to build more of everything from the lower corruption.