Gaming Nexus has an impressive preview of Galactic Civilizations II. Its preview highlights the differences between Galactic Civilizations I and II.
Suffice to say, Galactic Civilizations II isn't just a graphical facelift. With the move to a 3D engine, all kinds of new gameplay elements become possible.
Amongst the changes they discuss: The new colony system, ship design, fleets, and the campaign.
Read the whole thing..