Well, I confess I’m not really in a position to know for sure, since I only played three of the games released this year: BioWare‘s Mass Effect 2, Obsidian Entertainment’s Alpha Protocol and Obsidian’s Fallout: New Vegas.
So, it may be that there are other games out there that are better. Given BioWare and Obsidian’s excellent track records however, I doubt it.
If forced to choose, I would say F:NV is the best, followed by ME 2 and then AP. I pick New Vegas over ME 2 largely because of a few serious problems with ME’s plot towards the end of it. (Detailed by Shamus Young here.) F:NV‘s story is pretty out-there as well, but it was fairly consistent in the level of what it asked the player to believe from beginning to end.
As for Protocol, while I still maintain that it is a fine game that was treated most unjustly by the critics, there’s no denying it had some bugs, some poorly executed concepts, and even a few instances of sloppy or cliched writing. (By Obsidian standards, I mean. It’s still much better written than the vast majority of games.) I suspect that it suffered somewhat from Obsidian focusing heavily on making New Vegas all it could be.
I should probably mention that my evaluations of all these games were perhaps slightly tainted by the fact that this past summer, I finally got round to playing Black Isle‘s legendary RPG Planescape: Torment. It is, as I had heard, one of the greatest games of all time–surpassed only by what must be considered its spiritual sequel, Obsidian’s Knights of the Old Republic II–and I suppose that my judgment of these more recent games was clouded by it.