I've been really busy this year with things that are not games, so I haven't played a ton of stuff that came out this year. I'll be graduating from school on Saturday, though, so I'll have a little bit of time and hopefully a decent amount of graduation money to catch up on this year's titles before the Game of the Year features start rolling out after Christmas. What 2012 games are essential to finish before getting into all of that stuff? Looking back, I think the only major releases that I finished were Mass Effect 3 and Spec Ops: The Line. I definitely plan to spend some time with Journey and The Walking Dead. Other than those, what would you consider must-play in an effort to not have the year's best stories or individual moments spoiled for me?
Starting with The Walking Dead and Journey is a pretty good plan, so you're on the right track.
If you're purely interested in minimizing spoiler damage, the endings of Far Cry 3 and Halo 4 seem like possible points of discussion. I wouldn't be surprised if a certain aspect of Fez is discussed in a semi-spoilery way as well.
XCOM, Dishonored, Mark of the Ninja and Sleeping Dogs are games I've played that bears mentioning in a top 10.
I don't feel like I've played enough (or played at all in some cases) Walking Dead, Fez, Mass Effect or Max Payne 3 yet to really render a final opinion, so I'll try to play.
If you want to get out in front of the goty bombcast, then maybe play the story games first(I like Dishonored and Mark of the Ninja, but they don't have much in the way of story). At the same time, I guess puzzles in Fez can also get spoiled for you.