I mostly agree with Sanat's post.
I think there are some common-sense things that everyone can do with will mitigate any urban inconveniences that arise.
I dont see that having a 72hrs emergency kit and some bug-out bags ready is really fear based survivor mode. Nor is having a few extra bottles of drinking water in a cupboard.
Where I think it goes over the top is when people get into stockpiling guns, ammo, masses of long term food etc and are ready to surive a nuclear winter and over a year without food!
Make your preperations: Learn how to purify water, get a fire extinguisher, get some first aid training and supplies - then put it all away and go quietly about your ground crew duties.
A..
PS: I wrote up some of the basics here
http://projectavalon.net/forum/showthread.php?t=1859