6: Grand Theft Auto: San Andreas
This is a big one. At the time, San Andreas was the biggest game world yet. Instead of the traditional one-city game worlds previous Grand Theft Auto games, San Andreas gave the player a whole state to explore, not just one city. San Andreas mixed things up quite a bit. Three cities, backwoods locations, roleplaying game elements, a wide variety of mission types, a plethora of minigames and the Rockstar typical quite a bit too long main questline made San Andreas into a juggernaut of a game.
While San Andreas wasn’t quite as overly stylish as the predecessor of Vice City, it offered so many things to do, and that made it the purest, most vast escapist experience offered by a GTA game. As such, it remains one of the 00s biggest and best titles. Of course a special hat-tip belongs to the game that started it, to GTA III. But San Andreas was so much bigger, so much larger, offering such a completely engrossing experience, that it represents the pinnacle of open world criminal mischief gaming.