Mark Thoma has an excellent post on privacy. Actually, it's about more than privacy: he highlights a New York Times piece by David Shipler about privacy that is also about more than privacy. Both call privacy a "privilege." But some aspects of privacy, including many parts Shipler discusses, are not privileges: they're rights.
Consider these sentences from Shipler's lead paragraph:
The Supreme Court ruled that the police could break into a house without a search warrant if, after knocking and announcing themselves, they heard what sounded like evidence being destroyed. Then it refused to see a Fourth Amendment violation where a citizen was jailed for 16 days on the false pretext that he was being held as a material witness to a crime.
The first was a violation of property rights. The second was a violation of liberty.
Commenter Dennis Drew, on Mark Thoma's blog, links to some pretty disturbing videos of police out of control.