Interesting that the US Department of Defense has banned thumb drives. The problem is that they can carry viruses and infect computers - and if your nation's defense depends on these systems (and by extension in the case of the US so does the defense of the rest of the world) they need to be looked after. So no thumb drives, no CDs.
But if you're going to take this seriously let's have a look at other removable storage. Here's a list, top of my head, of potentially virus-carrying items I could lay my hands on in my office within 30 seconds:
'Flip' video camera
OK, it's only five and the voice recorder is really easily identifiable as storage. The media players and phones and particularly cameras are less so, though.
Tell you what. How about a new idea? Instead of all this stuff about singling out thumb drives and whatnot because they're a risk, how about ordering some new hardware - like PCs without a USB socket in the first place? We all know they're available, and if you really need a peripheral or something connected you could have a hub of some sort connected by WiFi. Then innocent people could carry their thumb drives, phones and cameras around with them without any need to worry - and malicious people with USB drives disguised as something else (I've seen pens, watches) wouldn't have anything to plug them into.
Someone's going to tell me why this idea sucks, I know they are. I just can't see the flaw in it from here.