9) The Professor Layton Series
The Professor Layton games are on this list, not for any frantic multiplayer action (I think they are saving that for the Luke FPS), but simply for the free content they provided. Upon release, all Professor Layton games provided a new puzzle for players to solve every week. It was an easy addition to make, but it exemplifies how Nintendo has tried to provide genuine value to its games through its online service.
Just like that found in Fire Emblem Awakening, the DLC was a great incentive to encourage you to return to the game long after the main story was completed.