For me it was Skyrim . Now now, do not boo me off the stage. It was the first RPG I've ever played, there was a lot of hype around it and I gave in. Loved every second of it, eventually even tried the ES MMO, but nothing stuck quite so much. (There's also a chance that Skyrim ruined me for other rps as well, so it's a double-edged sword since now I search for the next great thing and can't find it!)