Role Playing is not as dependent on the system as most people seem to think. It is entirely possible to RP without a rules system. Having said that, my favorite rules system is 3.5e Dungeons and Dragons, house ruled to my liking of course.

I just want to say that this post has rather serendipitous timing. I was just sharing a story about a game of Cthulhu I once played with my friends, with whom I role play pencil and paper style once a month. The situation was this - my character had managed to seduce another PC. She got pregnant, and so the PC in question did the gentlemanly thing and married her. Of course, she was very happy with this development because she loved the PC in question. Unfortunately for me (the player), the player of the other PC decided that a wife and child was too much of a weakness for him, and so at their reception, he laced the fruit punch with arsenic or something, and planted a cultist symbol in the bowl. Since she was pregnant, he insisted she drink the punch. She died. I was furious, and even to this day I am still angry about it.

There were three problem-

1. If my foggy memory is correct, I insisted that my PC probably wouldn't just drink the punch, since back then they didn't have doctors telling prospective mothers not to drink alcohol during pregnancy, not to mention that she was French, and accustomed to drinking wine/champagne regularly. The Game Master overruled me, and my character's PC husband insisted she drink the punch.

2. No one else died from drinking the punch.

3. I was given no indication by either the player or the Game Master this was coming. I was completely blindsided, and lost a character I had liked a lot.

I had no chance to avoid character death, and that really hurt - especially since I considered (and still do, actually) both the GM and the player friends. The fun of the game kind of vanished for me, my next character was designed specifically to get revenge - and because the player of the murderous husband PC, and his PC, were the GM's favorites, I was never able to win. Eventually his PC did die, but only because of several botched first aid rolls in a row which the GM could not just fudge away because they were rolled publicly by another player. I never regained my enjoyment of the game. Which is quite possibly why I don't play Call of Cthulhu anymore.

For me, this was not a good story. For the murderous PC and the GM, it obviously was.

Oops, I forgot to mention the Cthulhu game concerned above was set in the 1920s.