The
Civilization games (I and II, but not so much III) are good.
SMAC and its expansion are Grrreat!
Shogun: Total War, Warlord Edition is also a great game, and I think it meets all four Xs. I have heard good things about its sequels, but I waited for MoO3. Then I came back to SE IV, because MoO3 .... well, that's already been covered and we have no need to get Atrocities going again (think about your blood pressure!).