By far the deepest and extremely addictive strategy game for hardcore fans. Better sequel to Civ2 then even Civ4.
EU2 is a tremendous innovation due not only to the level of detail of representation of Earth, but to an amazingly deep and balanced game engine. Even at later stages of the game micromanagement on the level of each province is avoided. What makes this game infinitely playable is absence of "sure to win" strategies to take over the world. Any single other game I played can be reduced to finding weakness in AI and shamelessly exploiting it.
After accumulating over 1000 hours of EU2 gaming each time I play requires all my knowledge and skill to lead the nation to victory. Few overly aggressive moves and "coalition of willing" will tear your empire to pieces. Being big in this games helps, but at the same time presents you with the whole host of new problems to deal with (ethnic, religious, etc.). One will easily understand the problems of running huge and diverse powers (like Russia), when bulk of resources have to be spent on keeping country together (providing stability) vs internal development (industry and technology).
Event language allowed thousands of history fans who played this game to make their contributions by contributing more and more detailed and historically accurate events and personalities over past few years. I keep getting amazed when the game in "off-hand" mode would realize most of the tendencies observed in real history. As one would expect the further away from the start in 1419 the more minor deviations would accumulate. Paradox keeps tweaking game dynamics a bit as they keep learning from feedback by gaming community over all these years.
Other solid and good games like Civ3, Civ4 are good for people NEW to this kind of games. Anybody who enjoyed earlier games from Civ series would not gain nearly as much from recent installments as they can from EU2.