Fallout New Vegas. I was on a Call of Duty binge where it was the only game I played for a year, I even sold my PS3 so I could get the early DLC on Xbox. Eventually I just stepped back and decided I wanted nothing to do with the franchise anymore. I bought Fallout cause my sister said it was great, and it turned me back into a real gamer. I wouldn't be a Nintendo fan now if it wasn't for Fallout (I know, that sounds weird.)
Oh and also it's just an all around great game. My second favorite game of Gen 7.