WeRelate seems like an interesting and useful resource. I hope to contribute what I have and learn more about my relatives.
Ancestral lines that interest me:
1) Ancestors of William McClintock, who arrived from Ireland in 1803. His brothers came in 1809 or so, and all three died a couple of years later. I have a letter from their father (still in Ireland) asking for news... poor guy. William McClintock was the father of Rev. John McClintock, whose information I have entered in some detail (but the references contain lots more information about him). William married Mary McGowan, who had five children with him, then she married Robert McKean, had five more children -- and one child from each of her two families is an ancestor of mine. That was pretty confusing for a while. She then outlived Robert McKean too, and died in old age (90?).
2) Ancestors of Thomas Davis Ewing, my great-grandfather. He was a minister of the First Presbyterian Church in Kittaning, Pa, then moved to Fairfield, Iowa, where he was pastor of a Presbyterian church and president of Parsons College. He was recruited for this by John Calvin McClintock (what a lovely Presbyterian name!), the son of Rev. John McClintock.
3) Henry Boyden Blood: fought in the civil war, my sister married a descendant and has a trunk that belonged to him.
4) Nathaniel DeHass McClure of California, Pa. The above are all my mother's side of the family, McClure is my father's side. I have a lot of information, but it all starts with him -- who were his parents?
5) Ancestors of Mary Orr: John McClintock's wife. Thanks to how common the names are, it's hard to be sure, but I know she's the daughter of people named James Orr and Margaret Hawkins and I'm pretty sure that it's the James Orr born 1775, who I found in this database. She should have been born in the first 20 years of the 19th century, which would be consistent with her parents' marriage date, and according to John McClintock's autobiography she was the daughter of James Orr, Esq., and Margaret Hawkins, respected citizens of Washington, Pa (that's what esq. would mean according to wikipedia) -- there's a bio of James Orr in Bates' Biographical History of Greene County that says a James Orr had 4 daughters who married ministers, 3 of them Presbyterian, so that would be consistent. Of course, Presbyterian ministers were pretty thick on the ground around there at that time.
I'll enter more information about these guys later.
I was on Ancestry.com for a while, but found that the access to resources just didn't justify the price -- I could find almost everything on-line that i could find there, and it is also possible to use the Census Records (and all Ancestry.com records) from some census offices, for free. So when I found that nothing new was showing up, I dropped the subscription -- unfortunately, I keep getting their spam