How much information is the government storing on you?

I've not been a fan of the increasing power of governments to acquire information over the past few years since the attacks on September 11, 2001. Security laws are rarely repealed or weakened since politicians don't want to be seen to be responsible for endangering public safety, no matter how unlikely that outcome might be.

This article from Ars Technica shows how much information the U.S. government might hold on passengers who travel internationally. It rather concerning. 

Of course, if you've got nothing to hide, you've got nothing to fear. Or something like that.

But, how much does it cost to acquire and store thing information? And how much does it cost to analyse it? And more importantly, is there any actual benefit to the safety of the public from the use of this information?

I'm very sceptical of the benefits of any of these government programs.