Fable 2, Gears of War 2, Dead Space, and Fallout 3 were all fantastic games, but when I think of 2008, I think of the WoW expansion, Wrath of the Lich King! That expansion was peak World of Warcraft and I put hundreds of hours into that expansion. As a longtime Warcraft fan in general, it was so cool seeing Arthas again since Warcraft 3 (also top 5 best games of all time) and his return did not disappoint. It was an epic gaming moment when you finally fought him in the Icecrown Citadel raid! Amazing storytelling, even for an MMO.
Not to mention, one of the best cinematics ever in gaming!