Grand Theft Auto 4
Metal Gear Solid 4
LittleBigPlanet
Fallout 3
Fable 2
...and, the winner is *opens envelope* Of course!
Grim Fandango! Certainly my favorite game of 2008. I had never played it before, and it was a marginally better experience than any of the other nominees. I loved MGS4 almost as much, but Grim Fandango edged it.