The Elder Scrolls IV: Oblivion (PC, Xbox 360/2006) Guessed by S.Peelman and FOX
Playing through Morrowind was a revelatory experience for me, so it was only a matter of time before I tracked down its sequel on Xbox 360. While not quite as good as its predecessor, Oblivion is still a massive achievement in terms of storytelling, open-world game design, and cutting-edge graphics. As in Morrowind, it was easy to get lost in the countryside or in towns and cities, delaying the main quest to meet the colorful denizens of Cyrodiil, explore its caves and ruins, and find lost treasure and artifacts. I logged about 80 hours in Oblivion but I could easily have played for double that.