The Discovery Channel, along with AOL, did a poll last year to determine who were the “greatest Americans” in history.
They created a website that profiles the top twenty-five in the poll, and they have fairly accessible biographies of each one.
I’ve placed the link on my United States History page.
More useful, I think, than the site itself is the idea behind the site. In my United States History class I had students develop a criteria and then their own list of who they think were the “Greatest Americans” and then explain why they chose each.