I first began playing Rome: Total War before I jumped straight to Empire: Total War and Napoleon: Total War. I have not been disappointed. It's an excellent game that simply cannot be improved. You can essentially rule the entire world now! Having pirates is an excellent idea, too, as when I play a naval power (Spain, Great Britain, France) I have to dedicate resources towards fighting the silly pirates in the Caribbean. Gettof my islands!!
If you are interested in colonial strategy, naval/land warfare, trade and diplomacy, buy this game. You will not be disappointed!