Try Civ 3 on diety mode. Now thats not easy. The A.I can get stuff x3 faster than you. I have allways found Civ 3 a lot more chlenging. I love both RTW and Civ 3. But Civ3 is cool in the way you get to build your own kingdon and expand beyond borders. Also in the play the world exspansion pack theres some good maps. My personel favourite test of time. Huge map start of in historical locations can play from 20 something empires and can choose to start with or without cities. Civ 3 also gets very interesting later on diplomacy wise with mutal protection pacts e.c.t