I like a lot Sand box games (GTA IV, Elder Scrolls Oblivion, Saints Row 1 and 2, Fallout games), because you get a lot of freedom to do whatever and whenever you want.
Also, I enjoy a lot the Role Playing Games, like Dragon Age Origins, Dragon Age II, Elder Scrolls Oblivion, Fable... they're very inmersive and you identify yourself pretty quickly with certain characters.
My favorite games of all time are Fallout 3 and Fallout New Vegas: I love the post-apocalyptic fiction, besides is a first shooter game, a sort of RPG and a Sandbox for sure. When I got those games in particular I felt like on Christmas Eve.
I prefer PC versions, since you can mod and personalize the game to your liking, even add content that wasn't supposed to be played there.
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