I thought it might be a useful tool if we created a list of additional resources that we use to enrich our content. I'll start:
Coloumbus/Colonization: A People's History of the United States 1492-Present by Howard Zinn. Chapter 1 "Columbus, the Indians, and Human Progress" provides first hand accounts of Columbus' actions when he landed and shows a pattern of mistreatment of Native Americans by European settlers. It is a useful chapter because of its first hand accounts, and can also be used to prompt position papers regarding whether or not the endsof human progress justify the means, or can be used to examine possible bias.
The Constitution and Slavery: Founding Brothers by Joseph Ellis. Chapter 3 entitled "The Silence" examines Quaker attempts to eliminate slavery in the Constitution and helps students understand why slavery was viewed as a necessary evil.
Westward Expansion/War with Mexico: I love using A People's History of the United States 1492-Present by Howard Zinn, for this unit as well. Chapter 8 "We Take Nothing by Conquest, Thank God" is a great thematic parallel to Chapter 1. Chapter 8 illustrates how President Polk initiated a war with Mexico to gain California. Again, do the ends justify the means? How does/should the American government reconcile the disparity between the freedoms and wealth Americans currently enjoy, with the destruction that paved the way?