I am looking for a good single player game to play offline.?

I have plenty of multiplayer games to play online. I am looking for a good quality game in the following genres: RTS, RPG, FPS, Sports, Racing, Simulation, adventure. I have a pretty hefty computer so that is not really a concern. There are just so many games out there that are hyped out of this world by the companies, I want to hear from actual players of these games, which games are worth putting money for. (I already have asin's Creed and Crysis looks like most other shooters just with more bling.....boring.)