Though only a sample, the comments below reflect the opinions, perspectives, and ideas from teachers in our region.
Egypt's Golden Empire
http://www.pbs.org/empires/egypt/
I just used the information on writing but in the future, there are a lot of other good resources. The resources on hieroglyphics are fantastic and it allows students to try their hand writing hieroglyphs on the site.
Africans in America
http://www.pbs.org/wgbh/aia/home.html
The primary source resources on the website are awesome. I used it student teaching to discuss the history of African Americans through the Civil War. Each era has a "resource bank" which is a gold mine for any teacher looking for a good selection of primary and secondary documents. Each also comes with a summary paragraph which is nice to include for struggling readers. I find that with students who are intimidated with primary source documents, giving them a brief summary before hand really helps them work through the wording of the piece.
Ken Burns' The Civil War
http://www.pbs.org/civilwar/
It's got some great online resources (lesson plans, images, documents, etc.) but probably the most useful thing on the site is the index of the film. Because the film itself is so long, there is both an episode by episode guide that timestamps each part of the series but there is also an Educator's Index that gives an alphabetical list of topics and where to find them in the DVD. I only wanted to show brief clips from the video and this was really helpful because I could find the best clips very quickly. See an example here: http://www.pbs.org/civilwar/classroom/episode1.html
Lost Empires
http://www.pbs.org/wgbh/nova/lostempires/
It would be a great hook for students in a history class who are really into science.
Roman Empires
http://www.pbs.org/empires/romans/index.html
I've read through the lesson plans, though I'm not using any of them in whole, they do have some good ideas. One of the resources that is particularly helpful are the brief articles on the Roman Empire. They're a great reference for the students because they are relatively brief, have lots of good information and also are written at an appropriate level for high school readers. I'm going to use the Emperors section with its biographies for a mini-project that we are going to do.