My first character,
Claudia Hunter, was a good karma character that assisted Yes Man in creating an independent Vegas. Scavenged a lot, opposed any organized systems and fought for the little folks. Worked a lot for NCR, making their life a lot easier and resolved the situation with Gen. Oliver peacefully.
My second character,
ex-Colonel Autumn is a neutral karma character who helps people only if it suits his own ends and ideals. Scavenges very little and mostly uses currency to get his stuff. Uses companions a lot but cares little of they die (already lost Boone). Opposes all the factions, but will likely lean towards Mr. House for the sake of irony - he has a bad history of serving computers

My third character,
Justine Hunter is evil karma character who supports only herself. Helps all the factions as long as it suits her needs. Very cruel, she works for both sides at the same times. May end up helping Legion. Uses energy weapons. Scavenges little, and usually just tosses new equipment to companions.
My fourth character,
Troy Hunter, is neutral karma who supports Mr. House. Troy is an "at all costs" type who will always cut to the chase, always go through the shortest way. A lot of innocents die in his way, but in the end he is doing the right thing. Scavenges his equipment, is generally rude to people and cruelly smashes down the little folks if he just feels they are standing in his way.