I enjoy role-playing games and I've made no secret of my atipathy for the new Dungeons and Dragons and the company that makes it. What set of rules should you then use? The truth is that you don't need any rules at all. But if you must have some, try GURPS, the Generic Universal Role Playing System.
I've wondered on the fact that 90% of role-playing games must take place in a pseudo Middle Earth. I think it would be great fun to play around in a superhero, spy, or future setting. Of course there are rpg games that do that, but none of them enjoy anywhere near the popularity of D&D. Gurps lets you play in any setting. You can mix settings and have characters from one setting easily move to another. You will find GURPS books for fantasy, space, superhero, martial arts, and historical settings.