Don't you have to make sure that your items are insulated from the metal surrounding it?

I am not certain that insulating a stored radio from the metal container in which it is stored would help.
Being enclosed in a conductive material should prevent any voltage difference appearing accross the stored device, and therefore prevent harm.

Although not convinced that insulation would help, it costs almost nothing to ensure that items are in plastic cases inside the metal containers, and I have done this be certain.

Hmm, I had done a quick google last night and one of the papers warned me that an item should not be touching the protecting metal because that would transfer the charge. I'll have to see if I can find it again.
Better safe than sorry I suppose.

I've downloaded and read about 20% of this report so far. It is EXCELLENT material. Engineering and analysis based and well written. Easy to understand for those willing to spend the time (not the news media).

Thank you for posting the link.

http://www.au.af.mil/au/awc/awcgate/cst/bugs_ch12.pdf

Is only 28 pages and presents a good summary as well. Also explains that EMP is not lightning.

EMP contains E1, E2 and E3 pulses. E2 is most lightning-like.
E1 is what will fry circuits - even in your steel house.

No tinfoil involved. Very serious potential threat.