Comment: LearnLiberty had a great video series on...

the different variations of classical liberal thought. I'd highly recommend it.
Introduction:
http://www.youtube.com/watch?v=mc7ucjtzdHg
Milton Friedman & the Chicago School
http://www.youtube.com/watch?v=0gcx8_tnkDs
Public Choice
http://www.youtube.com/watch?v=ffJFNEujeL4
The Austrian School
http://www.youtube.com/watch?v=4hIax9gh7fU
Natural Rights
http://www.youtube.com/watch?v=Ysis1GfV0Qc
Anarcho-Capitalism
http://www.youtube.com/watch?v=1r99Ae6gmgg
Conclusion
http://www.youtube.com/watch?v=nVTryhCeddQ
It's not just about what the role of government is, but HOW does one determines what the role of government is.