In retrospect, I'd like to get some clarification from the OP about what they mean by "balanced". I assume that they meant "can wage wage effectively while not neglecting other areas". By that metric, I stick with Germany and understand people saying England or Poland. The people posting about the Zulus or Huns I have to disagree with: they can certainly kick a lot of ass, but I don't think they keep up that well in other game aspects. They're just really effective single-focus slayers of men and civ.