I kept meaning to post Populous on here but never got round to it.By the way, is it bad that in these times of disaster in Japan, I can't help but think about how awesome Populous 2 was?
It was a real next-gen game, something completely different only enabled by advances in technology. It had procedural terrain and massive AI for the time, and then the fabulous gameplay of powers that could be wielded in novel combinations like the planting of forests to have a forest fire.