To say that this game is addictive is like calling the center of the sun warm.
Yeah, I've played other turn-based strategy games, and some of them were really excellent. I can recommend Disciples 2 in a heartbeat. And yeah, Civilization III was like -- how do you say? -- electronic crack. (I will be enjoying Civ IV shortly, can hardly wait to try it out.)
But this game -- the gameplay formula (it's a thing of mathematical beauty), the animations, the towns, the music -- everything about this game lures you into a hypnotic state of absolute enthrallment. You'll sit there, eyes drooping out onto your cheeks, tongue down on your chin, bladder full, the hours melting away like an ice cube on a hot sidewalk. "One more turn, one more turn, one more turn," you'll feverishly play on while dusk turns to dark and dark turns to dawn. It's ridiculous. Finally, you'll close your eyes to go to sleep and still be thinking about this game as you drift off.
If you don't have a little time to waste, do not play this game. If you do have some hours to kill, and you like strategy games with role-playing (or character building) elements, then get this game. It is, as far as I am concerned, the king of them all.