It's an absolutely underrated video game franchise, mainly due to inactivity, but X-Com did some of the better science fiction in games for a few years there. X-Com: UFO Defense was an extremely deep (and tedious) turn-based game that had you defending against invading aliens one move at a time. I've always described strategy video games as chess but with lasers/battleaxes/aircraft carriers and I'm sticking to it.
We'll have to see how X-Com: Enemy Unknown adapts to the current generation of consoles, but we're putting this one on our radar for now. Check out the Casualties of War trailer and let us know what you think on Facebook.