I actually used to carry one of these:



But I found - repeatedly - that I'd run into outlets like this:


At airports and outlets like this at client locations:



And the right angle plug would be problematic.

So then I started carrying this:



But the 8' length was too much so I cut it to 4' and put this male plug on the cord:



(Yes, I cut the ground off - I know, I know, shocking)

It's great BUT now I'm looking at this gadget:


And I figure with one of these and that, I'm in great shape:
http://www.amazon.com/Coleman-Cable-6991-Liberator-Extension/dp/B001GLWL0O/ref=pd_sim_hi_5