There are a variety of multimedia googahs in the game. Little video snippets play for each event and when you win or lose. These I found to be of questionable quality and they interrupted the flow of the game. It's good, therefore, that you can turn them off. It's likely you will after a single game.
Sound effects are minimal, basically battle sounds when a region is attacked.
They are fine, but there is no need for them. I quickly turned them off. The music is fairly good, in character with the epoch you are playing. While it isn't something you'll play in the car on the way to work, it fits well with the game. Still, after a few games I turned it off and listened to my own CD on the stereo.