Nobody's mentioned Chu Ko No yet? I love Chu Ko Nu. They come at a very good time in the game for me, they get 2 first strikes, +50% vs melee (and melee is always the biggest threat facing me at that time), and they cause collateral damage. Where I never use crossbowmen playing another civ, I always pump out Chu Ko Nu as the Chinese. They're walking catapults with more uses.