This is by far the worst aspect of the game. It keeps me from playing on higher difficulty levels because I get so frustrated. The AI is decent, but the coding that keeps them from attacking each other is ridiculous. Now I know they do fight some, but their timing and reasons are not even close to making sense.
I spent 4 hours last night with two French cities pumping out culture. I was FAR behind in the technology and economic race, and yet FOUR other civilizations chose to wage massive war with me, their only demand for peace requiring me to send them a Great Person. Now I can handle and understand war with my close neighbors, but the other civilizations were all much closer to each other than me. Yet they continued to prosper as I stalled out pumping out defensive fodder unit after defensive fodder unit until I got so far behind in technology that I could no longer hold off four attacking civs. Very, very unsettling... I laid awake all night trying to think of what I could have done differently.
It's really too bad, because I reckon a patch could fix this problem somewhat. Until then, it looks like I'm gonna move to Civ IV where I have an actual chance to succeed.