I believe that people are entitled to privacy in their communications... which may only be infringed upon as a result of due process. I do not believe that a blanket approval of a spying campaign of gigantic proportions (spying largely on anti-war groups and the like) constitutes due process. Furthermore, I believe that this is yet another step by our government in consolidating its power with full intentions to make it as close to absolute as possible. As someone who has lived in a country where the citizens had no expectations of privacy with regards to their government, and where disappearing for criticism of the state had been a common occurrence (largely before I was born, but my parents remember), I feel I have a much better perspective on this, compared to people who hadn't lived under a totalitarial regime.
Bush's excuse - the perpetual "war" seems awfully Orwellian, not just in content, but even in phrasing. In essence, he is saying that to protect us, he has to take away exactly the things that we want to protect. It's like a security guard awho will protect your house for you, under the condition that from then on it'll actually be his.