#4 Mass Effect 3
Shepard has returned, and so have the Reapers. Mass Effect 3 shows an Earth besieged by an armada of Reapers, and the only hope of humankind's survival depends on Commander Shepard.
Mass Effect 3 brings back the role-playing and action elements of the first two games with a number of improvements, and it takes all the events of the first two games into account, provided you have a save file to import and carry over to Mass Effect 3. All the actions you commit in Mass Effect 2 are therefore etched in stone, and you'll have to deal with the consequences.
Save for the game's ending, we can't think of anything bad to say about the game.