Gamespy has a really good preview of beta 4 of Galactic Civilizations II. 

The preview touches heavily on a feature that hasn't gotten a lot of attention yet -- diplomacy. 

While GalCiv II has plenty of features for those who enjoy warfare and strategic combat.  But immense amount of effort have gone into the diplomacy engine of Galactic Civilizations II.  With 10 different civilizations to choose from, we have developed tools that came from our last game, The Political Machine, to make it easier for different species to have different personalities, reactions, and strategies in diplomacy.  The result we're aiming for is that each civilization will truly behave differently and require different strategies based on which civilization you play as.  The Gamespy article touches on this as the author of it is very familiar with the GalCiv series (he reviewed the original GalCiv for instance).  It's a great read.