Possibly The Ultimate Grand Strategy game.
User Rating: 9.5 | Europa Universalis III Chronicles PC
The best most complete grand strategy game. If you love the time period, the style of gameplay and the vast scope of taking any number of nation states through a roller-coaster ride in history then this is the game for you. Even though I just do not have the time to play this as often as I would like its is one of the few games that never leaves my hard-drive. Like an old friend it is always there to let me play a few years of game time.
With so much detail incorporated into the mechanics, it is a armchair strategists (like me) dream, but doesn't get bogged down in warfare too much. It's perhaps the most balanced Grand Strategy game across the Paradox collection, its where I first started (EU2) and where I invite you to do so to.
With all three expansions included this is simply an amazing package. Its one for anyone's collection. 
