1. First on the list would be the outstanding public records and marriage license site maintained by Jackson County, Missouri (Kansas City area). On this site, one can find copies of marriage licenses in either PDF or TIFF format. An individual record package will include the affidavit of age and, if necessary, the affidavit of parental consent. I've found records, with images, as far back as February 1827. That's 180 years of marriage licenses! This site is kept up to date and has very few errors. It's easy to use. It is my favorite public agency site.
2. Missouri Secretary of State's Death Index. This remarkable site has indexed Missouri deaths from 1910 to 1956. Images are available for all years except 1931-1949. This site has a lot of volunteer work in it. Images for the remaining years will be posted as scanning is completed. The images are downloadable. For records for which a scanned image is not available, photocopies may be requested. The cost is $1.00 if ordered from the State Archives and $5.00 if ordered through the Friends of the Missouri State Archives. The "Friends" will provide faster service.
3. Corpus Christi (Tex.) Public Libraries. My favorite part of this site is the local obituaries index provided in cooperation with the Corpus Christi Caller-Times newspaper. The index has obituaries from January 1950 through January 2007. The library staff will copy, scan, and e-mail two obituaries a month in response to e-mail inquiries. The staff will also photocopy and mail up to five obituaries a month to requesters who send a SASE. I've found the staff pleasant and always ready to help. Their services are timely, which I always appreciate. But there's more to the Local History Department than just obituaries. There is a "1883-1903 Select Index," which includes abstracts of material from the earliest remaining issues of the Corpus Christi Caller. The earliest issue on microfilm is 1883. This database covers articles that were published through 1903. Events available include births, deaths, marriage reports (indexed by groom's name), divorces, and early black history. But, wait, there's more! There's a collection of historic postcards two other photo collections, and a collection of individual and family papers. And there's a great part of the site devoted to Corpus Christi's Old Bayview Cemetery, with photos or documents for almost every name. There are resources for black history, Hispanic genealogy, and links to the Southwest Jewish Archives and the Sephardic Genealogical Resources. And they've got the hard to find Church and Civil Records of South Texas & Northern Mexico on microfilm. The central branch is at 805 Comanche, Corpus Christi, Texas 78401.
4. Gregg County (Tex.) Clerk's Office, Longview, Texas. This East Texas county has a web site almost as good as that of Jackson County, Missouri. That's not a surprise, considering that both counties hired Hart InterCivic to set up their sites. One difference is there are no actual images of certificates on the Gregg County site. In May, 2004, I went to Longview, Texas, to research records at the Gregg County courthouse. The actual clerk's office was easy and friendly as the website. Records were easily accessible. In fact, my only criticism is that some of the older records are too easily accessible for sake of preservation. Otherwise, the County Clerk and her staff are to be congratulated for running a topnotch operation. One employee, Gloria Caraway, spent over an hour with me tracking down a death certificate for my 3rd great-grandmother, Amanda McCray Bowie (1848-1924). A research visit is well worth the effort. The office is at 101 E. Methvin, Suite 200, Longview, Texas 75601. The mailing address is P.O. Box 3049, Longview, TX 75606.
5. TSHA [Texas State Historical Association] Online. This is a public agency site because it's hosted in cooperation with the General Libraries at the University of Texas at Austin. The specific part of the site I'm highlighting here is The Handbook of Texas Online. As the Handbook itself says:
The New Handbook of Texas is a multidisciplinary encyclopedia of Texas history, geography, and culture. It comprises more than 23,000 articles on people, places, events, historical themes, institutions, and a host of other topic categories. The scope is broad and inclusive, designed to provide readers with concise, authoritative, and accessible articles that provide factual, nonpartisan accounts on virtually every aspect of Texas history and culture.
I've found relevant biographies, among other things, here. I really enjoy the historical articles.
Visit these public agency sites either in person or on the Internet to get a sense of what outstanding sites look and feel like!