So I've blown up Megaton and done a few other naughty things (like persuading the old guy to jump off the top of Rivet City) but going round killing innocents just feels so...wrong. Which I guess is right but doesn't make it any easier. I had to kill all the slavers at Paradise Falls because I dropped a grenade in one of their pockets (that felt good) and killing some of them netted good karma so I killed some of the slaves to balance it out. Not the kids though, I wanted the XP for the quest to free them. But I thought about it.
I'll be glad when I finally get that level 30 Evil achievement.