The gameworld is more expansive, and the simulation model is significantly more elaborate than the first go round, so if you like that sort of thing, then this iteration will probably be to your liking.
As far as graphics go, I've got a pos 128Mb PCI Nvidia card that it runs fine on, though there are slight pauses when reupholstering furniture and the like.
Funny thing, my wife loves the game, and I call them her dollies, but when she saw me fire up Civ III for the first time, she said it looked like the most boring game in the world.