A must buy re-imagining of the classic XCOM: UFO Defense (US) and UFO: Enemy Unknown (UK/EU) from the 90s; this edition has the unusual distinction of taking a classic, reimagining it and possibly making it a better game.
Run the worldwide anti-alien response team by building bases, shooting down UFOs and command gun battles on the ground. The game has a strong story with a good research tree that keeps the challenge real. The DLC is worth having with the Enemy Within adding a bundle of interesting content.
The only flaw with the game is that the 'on the ground' battle sections can get a bit repetitive if you aren't testing new toys your scientists have dreamed up in the field, but overall the combat is much more enjoyable than previous incarnations by seriously reducing the amount of micromanagement.
I wouldn't recommend buying it with The Bureau which was a more poorly received console shooter which is only worth buying with 90% off.