Egypt, for all reasons that red harvest has mentioned.
And then scythia.
Their armies consist of 8 horse archers, 8 normal archers, rounded off by some chosen archers.
I could allways cry when my usually very infantery heavy armies meet a scytic archery force.
I feel like facing a modern days army, being shot in little pieces without ever being able to get in contact with the enemy.
And once you somehow manage to defeat them, you get ridiculously large areas of completly wortless land that is only good for spawning rebels.
Disgusting.