I'll play pretty much any character type, but I need the freedom to make my character quirky or unique in some way. I'll always choose a character with weaknesses or flaws. I don't play PnP RPGs to have the experience of succeeding all the time (that's what videogames are for); failures and setbacks are dramatic opportunities. I like that.

As a GM, I prefer games with realistic motivations where everyone, including the "bad guys", sees *themselves* as the heros of the story. No monolithic evil. Bad guys do bad things because they think they are necessary, not because they're psychopaths. I like games that are gritty in tone, with a mix of successes and failures (though my current game is running in more of an action-movie-hero mode, and the players are really digging it).

The only system I've run or played in years is GURPS, though a friend has run a session or two of Champions (superheroes using the Hero system). I much prefer these systems to any incarnation of D&D.