While the Opposing Viewpoints database is still your best source for argument papers, ProCon.org offers a brief list of pros and cons on a number of hot topics, including standardized tests, illegal immigration, and privatization of social security. Features include a brief overview of the controversy, a timeline, the top ten pros and cons, and a brief back-and-forth over selected core questions.
What sold me on this website, however, is the presidential candidate questionnaire. Answer a few yes or no questions about hot topics and you will see a graph that shows which candidates agree most closely with you. It’s a great tool for the classroom.