Let's dissect that for a moment....
Precisely what do you do which makes you a terrorist or a potential terrorist every day? Read books? Who doesn't read books? Own firearms? Isn't the same party accused of creating the fascist database also the one solidly behind gun ownership rights? Buy things? What things? Do you need 2,000 pounds of fertilizer if you work in Information Technology?
Does anyone here really think that reading a book about obselete WWII techniques or even about Arab terrorist history makes you a terrorist? Now, hold that thought....
Well, that's not a logical progression. Just because we have 40,000 nuclear warheads doesn't mean we're intending or even would dream of blowing up the world, even though it's theoretically possible. The point is that you could have a supercomputer spit out all sorts of data every day, but computers don't arrest people or conduct investigations. Trained agents do that. While you can spit out a billion matches to some sort of criteria an hour, you can only follow up on so many in a lifetime. Unless you end up buying 2,000 lbs of fertilizer and are not a farmer, or some such concurrence of suspicious facts that would have been checked out anyhow if they had been discovered via a seperate means, you don't even rate a phone call. There's not enough people to deal with you.
Now let's put this all aside and think about something else. Whereas no one wants to have some sort of governmentally controlled information system on all of your facts, at the same time people increasingly want their government to take care of them in different ways. When people discuss a National Health Care system, sometimes proponents discuss the architecture that would be required to manage such a system, but it is generally shyed away from. Why? Because a national health care system would have to compile a great deal of information about you to even operate properly. That same information could be tapped just like any counter-terrorist database under consideration now, if one wished to act illegally or simply unethically. Already Social Security has produced a number that your life now generally relies on in the US, the Social Security Number. Sure, you don't have to give it to people, but then, they don't have to sell you anything or loan you money either.
The fact is that what the government is doing is simply reacting to the trend towards people relying on government to take care of them. The only difference now is that it's a little more straightforward of a percieved threat. The problem is that while we sue the government to stop actions like this, some of the same people and political forces leading the privacy pack are manuvering to push mandates and federal programs that have the same potential for danger. The difference is the sugar coating. I'd say that a national database coated in a health care system or national gun registration system is ten times more dangerous simply because it comes with a system that no politician would dare attack once it was in place. Even the Republicans wouldn't dare ever touch Social Security, and so the numbers that come with it are the gold standard of information retrival today because we all know that.
The point? The problem is not as simple as it looks. You want terrorists caught in an increasingly sophisticated world, you have to collect information quickly and make matches proactively. As has been said, we have to be both proactive and correct 100% of the time or people die. The terrorists only have to get lucky once. To be proactive and be ready you need intelligence. The other option is failure and people dying....the ultimate loss of your rights.
Governments have turned totalitarian with a whole lot less technology than this at their fingertips. If the US is going to turn into a dictatorship, it doesn't need the help of a supercomputer or your bank statements. However, fighting terrorists does require every bit of muscle that can be thrown at the problem. Pundits like to tell you the worst case scenarios for situations, that way, they are never wrong. However, a population that can work with its government and endeavour to understand it rather than simply put it at arm's length or oppose it in a kneejerk fashion will succeed in protecting itself the best from excesses.