I'd imagine New California Republic would let good players join. They can always bring back the rangers who fight against slavers and general evil. The option of becoming a professional slaver. Probably Brotherhood Of Steel since they always show up in these games.
http://i2.photobucket.com/albums/y8/akuma634/a.gif You haven't lived until you've seen a spider monkey rape someone in the eye - Steve Wik on Postal III
Yea exactly! I save the world almost single handedly and I get pooed on. And if there are multiple factions, there should be conflicting ones that you can't join if you're in the other. I thought that was so lame in Oblivion I could be the leader of the FIghter's Guild and still work my way through the ranks in the Thieve's Guild.