Which game/games has the most complete and immersive gameworld ever?

In your opinion, which game has the most complete and immersive gameworld you have ever played in(well so to speak? Feel free to mention more than one and why and please think hard about this question and not just write the game you completed last night, because its in your recent memory, unless of course it happens to be that game. There are so many fantastic games with fantastic gameworlds, so its hard to choose

I choose "The Witcher" - Reasons: Atmosphere that is unbelievable. The world is dark and gritty and feel lived in, the story is fantastic. The game is long and never gets boring. The bestairy is so unique and fantastic. The music is amazing, the characters are interesting and the gameworld is full of mystry and lore!

dragon age origins. the world is amazing and the interaction is most immersive

A few of the games I was thinking of have already been said fallout3,mass effect,gta4 but not these

fable 2 looks amazing and feels real, and because of one area, the winter lodge demon door was amazingly epic

I haven't played a game that can do immersion better than STALKER. The look of the word, the sound production, the NPCs, and everything else just comes together so well. There's enough of a story to keep you moving onto other parts of the game world, but the real fun is the exploration.

I haven't played a game that can do immersion better than STALKER. The look of the word, the sound production, the NPCs, and everything else just comes together so well. There's enough of a story to keep you moving onto other parts of the game world, but the real fun is the exploration.

ProudLarry

Very well done; running around in the night in a thunderstorm with only the flashlight lighting the way with mutants screeching in the distance was fairly intense.

No game has topped Super Metroid for me, mostly exclusively due of the music. If the importance of good sound is any indication of an immersive gaming experience, then SM is a prime example.

The Grand Theft Auto games from III and on. The design of the neighborhoods and cities, the change in weather, driving from place to place while playing any of the radio stations, have always been very well done. After awhile you start to feel apart of that world.

fallout 3, starcraft, command and conquer