Fallout 3 has got to be the considered best role-playing game, easily.
Fallout 3 setting is in the near future of Washington D.C. You begin your the game as if you would in real life, You are born. Unfortunately, your mother was unable to survive your birth and your only form of siblings is your father. As soon as you learn to walk, become ten years old, fired your first rifle, and took the G.O.A.T. Test, Your true life in Fallout begins.
Fallout's story takes you in the very first second of the game after you have completed your character creation. Fallout 3 has dozens and dozens of hours of gameplay. The main story line will keep you well informed and interested. Everything in Fallout 3 has its own beauty, whether its the relaxing soundtrack while crossing and open field or the graphical techniques while dosing off into the sun set while walking on a beach. In order to fully complete this game, you must be willing to play 100+ hours just to get "mostly completed", but that should'nt be a problem.
P.S. - Be careful of RPG ADD, it could add a lot more hours of gameplay.