I just read that you guys at Stardock are taking care of your own advertising and such. I wanted to recommend that you get in touch with Gabe and Tycho over at Penny Arcade (www.penny-arcade.com).
I imagine yall have probably heard of them.. but in case you havent.. they are an online web comic that reaches millions of gamers every monday, wednesday, and friday.
In order to "keep it real".. they only advertise for games that they are excited about..or enjoy playing.. or..well..things of that nature. Tycho..the "voice" of the comic will be a big Galactic Civilization fan.. this is just his kind of game, and I know we are gonna see him commenting on it as soon as it comes out. In the mean time.. I figured yall may want to see about advertising on their site, because those adds get alot of traffic.