Firaxis (Civilization, Alpha Centauri) is remaking the original X-Com: UFO Defense (known as UFO: Enemy Unknown outside the US). It's going to retain the combo of turn-based strategic combat and management meta-game. It'll feature classes, stat development and persistence for soldiers, agency management, base-building (with 3D exploration of bases possible), and a host of other stuff.
I'm watching this one very, very closely. X-Com is easily a top-3 game for me, alongside Half Life and Diablo II. The sequels got a little less great each time--Terror From the Deep was quite good, but Apocalypse lost some of the charm. After Apocalypse nothing from the X-Com universe was worth bothering with.
http://www.rockpapershotgun.com/tag/xcom-enemy-unknown/