Immersion. It's the key to a great book, a fantastic movie, a can't miss TV show, and especially to a video game. It's also one of the hardest qualities to achieve. There are so many breakers in a typical game, what with load times, saving games, poor AI, graphical (especially clipping) issues, and the biggie, death. To find a game that can pull you in on the story/gameplay combination alone is unusual. Finding one that can do that, while overcoming the aforementioned inherent properties of gaming, well, that happens far too rarely.
But happened it has in 2008, with the release of Fallout 3. Despite playing fewer games this year than in the past, I was thinking of not even bothering to award this title to anything. But after the initial play session lasted ten hours, it was clear that not doing so would be a disservice. This game is good. Real good. Fantastic. If you haven't played it, you need to do so. Please. Hurry.