You my friend have just made my day WHY well a fair while ago I stumbled upon the site of ref and then lost it but now it appears again thanks to you . this site has all the death certs that one needs if your ancestors lived here as mine did now beat that.
Its been mentioned, but it bears repeating and repeating and repeating: Google Books. Its a source that gets better and better all the time. I've made a number of pretty astoundingly cool little finds that just would not have been possible in the past, no matter how much money had been spent, how many archives visited, and how much film pored over.
I enjoy using several resources. Rootsweb.com has been a tremendous help to me recently. I have been researching the lineage of my Great Grandmother Mary Rose (Sutherland) Farmer and could go no further, through Ancestry.com. On Rootsweb I found members that had traced the family to the 1700's.
The other site I find very helpful is Findagrave.com. They list cemetery information. What is very interesting is the ability to leave messages and virtual flowers at their grave. I have linked with other researchers in this way.
http://jewishgen.org/ - The Home of Jewish Genealogy - Free Jewish Genealogy databases (no searchable free within Ancestry.com but for some reason I don't like their display as much)
http://www.yadvashem.org/ - Yad Vashem The Holocaust Martyrs' and Heroes' Remembrance Authority - The Central Database of Shoah Victims' Names has pages of testimony and information you can't find anywhere else.
If you have 18th cent. ancestors in Virginia, particularly of some property, this is VERY worth your time.
Binns & Co have put together a pretty amazing set of "1790" and "1800" Virginia tax lists at Binn's Genealogy. These are fully indexed (and very well indexed in my experience) and they replaced the old scans with larger ones last year so even if you've visited them in the past you might check and see if you can snag a bit higher quality image now.
The Library of Virginia is also a real treasure of course, particularly for their digitized 17th to 19th cent. patents.
The Univ. of Okla.'s Western History Digital Collections includes, fully digitized and searchable, two collections that are exceedingly valuable for anyone with IT or pre/near-statehood OK ancestors:
The Doris Duke Collection>: The Duke Collection of American Indian Oral History online provides access to typescripts of interviews (1967 -1972) conducted with hundreds of Indians in Oklahoma regarding the histories and cultures of their respective nations and tribes. Related are accounts of Indian ceremonies, customs, social conditions, philosophies, and standards of living. Members of every tribe resident in Oklahoma were interviewed. The collection includes the original tapes on which the interviews were recorded, as well as microfiche copies of the typescripts. The digital representation of the typescripts are organized by tribe but may be searched by interviewee, by interviewer, by tape number, or by keyword searching of the full-text of the transcript.
Among them is my own g-grandmother's interview, occupying one full side of an audio tape, running 12 pp in transcript, and filled with things that would've otherwise been lost forever.
Indian-Pioneer Papers Collection The Indian-Pioneer Papers oral history collection spans from 1861 to 1936. It includes typescripts of interviews conducted during the 1930s by government workers with thousands of Oklahomans regarding the settlement of Oklahoma and Indian territories, as well as the condition and conduct of life there. Consisting of approximately 80,000 entries, the index to this collection may be accessed via personal name, place name, or subject.
These were gathered from White, Black, & Nat. Am. folks alike.