For me its Castlevania: Lord of Shadow. I wanted to get the game when it launched, unfortunately I got distracted and went off the radar until I got it for cheap recently. I must say, wow, why didn't we hear a lot about this game? From the reviews it made it sound like an average game, but is much better than the recognition it got. This game is a wet dream for someone who is a huge fan of Dark Gothic architecture flanked by sweeping vistas stretching all the way into heaven; haunting soundtrack and everything else which resonates with Dark Fantasy. The combat may appear hack and slash at first, it is different and more tactical compared to something like, say, God of War or Darksiders.
Overall, great game and wish a lot more people actually played it. Here is me anticipating the sequel to the game :)
What is according to you, the most underrated game this console gen so far?