Free online genealogy tools are like gifts from above. Which one are you most thankful for? How has it helped your family history experience?
It is difficult to pick my favorite free online genealogy tool. But since many, many of my ancestors are from West Virginia, I'll chose the West Virginia Division of Culture and History. The main tools I use there are the databases at the West Virginia Archives and History section. Mostly the birth, marriage and death records, although I definitely need to explore the other resources as well, including the West Virginia Memory Project. I believe most of these records are indexed at the Family History Library now, but I often have better luck searching from the West Virginia site. If I can't find someone in one index, I'll try the other.