Although it showed up in the very techno-centric "Register", I think this article is a must-read for anyone concerned with privacy rights in general. The author is the former head of the federal computer crime unit, and makes a very basic point on how computers are different than the rest of the luggage we port around with us.
For most things, when we travel, we take the bare minimum with us -- the items we need to enjoy our trip and take care of ourselves. But in our computers we carry around information about our entire lives -- contact lists, email history, personal and legal documents, etc. The idea that the government has unlimited powers of inspection on electronic devices is akin to saying that every time you board an airplane, the government gets a free search warrant for your house.