One of the better games to come out this year.
A couple of minor things that seem to be missing from the game that would have made it perfect: tactical combat, a more detailed tech tree (not just Laser I, Laser II, etc.), the ability to terraform inhospitable worlds, and a library of pre-built ship designs (minus add-ons). The game is still great without them, though.
The one great thing about Galactic Civilizations II is that the game ships with absolutely no copy protection on the CDs. You do not have to put the CD in your drive in order to play the game, but you do need the serial number in order to install updates, which I consider a fair trade. Stardock is one of the few game publishers that doesn't treat its customers as software pirates.
Don't walk, run out and buy this game.