What are reasonable limits on our privacy?

A second edition of the FBI's "Domestic Investigations and Operations Guide" is currently under revision and will be out on October 1.  Is this a new and improved version?  Hardly.  While emotional rants from organizations like the ACLU are expected in this and all similar cases, a saner review tells you that it's just more of the same—and that's the problem.  What are reasonable limits on our privacy?  How much of our privacy are we willing to lose in order to protect ourselves from...