I have to say, all around, I like the Egyptians and Celts best.
War Chariot is cheap, early, and resource-independant. I got them, built one, got into a fight with the Japanese, entered a Golden Age, built about 400 or 500 thousand War Chariots (or maybe just thirty) and wipe them off the map.
Celts, also very similar... 3/2/2, for iron, and how can you NOT love those pants?
TO quote Blackadder:
Roman Georgius: "Why are we fighting the Celts again?"
Roman Adderus: "Because they are a threat to our mighty Empire."
Roman Georgius: "But we're Romans! We're smart, we're civilized! We have roads, art, music! We wipe out bottoms with scented papers!"
Roman Adderus: "Yes, and the Celts wipe their bottoms with Romans..."