Sims? I hated that game... my people could never stay alive and the creepy music was scary when the Grim Reaper would come walking down the sidewalk. I prefer to come up with stuff from my own head. Music is a good helper too, though.
I've always simply brainstormed a character that I could connect with somewhat. Though I would always try and associate them with other characters from different stories.
Go with your instincts. At least try it. It may be your most effective means of character creation and development. I don't believe in developing characters in advance. I begin with a minimal set of characteristics, and then let the story bring out the details. At many points, I'll have decisions to make on how a character will react - that's when nuances get determined, when I think about what each possible decisionsays about the character, and then make the choice. To plan the character in advance unduly constrains the story flow, at least for me.
