I steal quite a lot of stuff, but don't pickpocket often (namely because last time I did, I managed to set the whole of Megaton against me). But I still have quite high karma, as I don't bother killing that much. The only notable place being Arful (?, the place were Lucy West's family live).
I did however make a file in which to be a git, and blew in Megaton, not before negotiating my fee up 500 caps. And then once payed subsequently killed Burke and Tenpenny, as I liked their clothes, and using a combination of missiles, grenades and a flamer proceeded to kill everyone in Tenpenny Tower.
And finally I made a neutral file, were I told Lucas Simms about Burke, who upon confronting Burke, was killed, then I killed Burke and looted both bodies, then defused the bombs, and celebrated by killing the caravan traders outside Megaton, (who I would recommend killing at the start, as if you can kill them, they drop some good stuff, you can make a quick cap selling the unwanted stuff, and the respawn quickly).