Tell me about it, On this playthrough I went from having no rep with the Powder Gangers to villified after killing only one of them. I was still in Goodsprings then.
That's what happens to me every time from day one. I'm fairly convinced it's a bug or something, since the other factions require at least...oh, say, three.

So your saying the factions should be ok with the first couple of murders?
It's ridiculous that they even can "know" about the murders most of the time. I killed everyone who could report back to the "faction" that it was me who killed them all. But beyond that...gameplay wise, for a new player who has no clue what side is up or down, killing 3 people and becoming Vilified is far too fast. I think it should be more like 10 or 15, or based a lot more off the quests vs. just the self-defense killing of npc's. The Powder Gangers, for instance, fire at you first. There's not even a period where they're blue/neutral like with the Legion & the NCR.