Socialism
Omnipotent Government
Collectivist Economic Planning
Economic Calculation in the Socialist Society
The Socialist Tradition: From Moses to Lenin
Karl Marx And The Close Of His System
Requiem for Marx
Marxism: Philosophy and Economics
Revisiting Marxism: A Bourgeois Reassessment
I would really advise against getting up there and defending corporations. Everyone will hate you, and there’s no reason to do it anyway. Instead, critique the current distribution of wealth from a libertarian perspective. (The Center for a Stateless Society has a lot of good resources.) Real exploitation is being robbed by the government at the point of a gun. You should probably also be well-read on current issues: inequality, the financial crisis, etc. Go to the Cato Institute for ammunition.