The Mississippi State Historical Text Archive is a great place to search for historical materials. The site holds (or has links to) a variety of African, Asian, European, Latin American, and American historical resourses. Furthermore, the site is associated with Mississippi State University, so commerical interests are not the primary focus.
The homepage of the American History Company is an example of a poor web site. The site offers few free resources for visitors. Commerical interests are the primary focus at this site.