To me, the best strategy game ever made, and you get to learn history and geography while playing. Also, you're not only getting the game, but all the expansions (4) with it. Seriously.
My advice. Play your first game as Castille (in Spain), it's in Europe so you get all the benefits like better military units, faster technology, etc. Also, you have easy picking fights next to you (Grenada is the last Muslim holdout) so you get target practice to start learning about war stuff. Do keep your infamy low (by not grabbing things that you have no right to) and do get stability to 3 (goes from -3 to 3) and you'll be set for a nice ride.