
In the case you still have not decided to buy Civilization 5, you can get it now for free if you preorder Firaxis new title XCOM: Enemy Unknown.
This only applies, if enough people preorder XCOM, and this threshold has not yet been hit. You don't have any disadvantages if you preorder it now, because you'll still get it if the limit is reached. Currently nearly 50% of the needed preorders are placed, and since it's still one month to go, the chances that the limit is reached seem pretty good

And in case you already own Civ5: You can also gift the copy to somebody else

If you have not decided yet if the new XCOM is something for you, you might also want to check out the latest "walkthrough" by Firaxis lead designer Jake Solomon:
And thanks

In case you're interested to talk about the Civ5 aspect of this news, please see this thread, and if you'd rather like to talk about XCOM, see our thread in the "All Other Games" section.
Please note that the minimum requirements have recently been released, and that you will need at least Windows Vista, 20 GB of HDD space and a Steam Account for XCOM.