I'm probably a really noob gamer when it comes to 4X space strategy games, but I've playing GalCivI for several months and totally loved it. I found GalCivII for $20 at gamestop and bought it. I just started my first map on it and man I'm having fun. The jump from the first one to the second one is amazing.
For the price you can get it for, it's a steal. I had the same issue you had. "Am I really going to pay $40 for a five year old game?" But then I found it at a price I was willing to pay.
I don't know if this is a used or a new copy, but with all retail bought Stardock games, when you register the serial number with them on Impulse, it makes the game available for download literally rendering the disc you bought as a backup. I mention if it's used because if the original purchaser registered online, it seems to stay with their Impulse profile. Not a 100% sure on this though, but I've seen similar issues like this on other boards.
On a side note, I just complained about them never having a sale on Elemental digitally, and I just bought it again for half off the Impulse price for $20 at walmart. I don't know why they don't ever seem to drop the price on their games, but they probably figure that most people that use Impulse are also probably Stardock game fans, they don't have to lower their prices to make sales.