@Setanta,
In addressing this question I think we should differentiate between "Being Watched", and "Being Seen".
I don't believe any government (or organization) has the ability to actively Watch everyone. What they do have is the ability to watch large swaths of data and large parcels of property and to try to focus on things that appear unusual. And while that may not be much more comforting when it comes to worrying about Big Brother, I do think it's an important difference.
I would like to think (and to hope) that government is only spending its real (and limited) efforts on what it considers high value or high probability surveillance.
And at the moment, I'm not very worried about the large scale surveillance of public places and the collection of public data.
As I think I mentioned in the other thread, I'm far more concerned about the ability of the government to force private organizations to give up their own (privately collected) data merely to increase the volume of the data they are able to scan. It seems to me that data collected and owned by private firms (or individuals) is private property, and the government shouldn't have the right to acquire it without specific reasonable cause sufficient to require a specific warrant.