I'm an avid RSS feed reader, and today Wired was linking to a Royal College of Art student's re-invention of the three-pin plug. Personally, I'm very impressed, and could easily see this becoming the new standard. The overarching principle is that it folds.
(original page here; Comprehensive design page here, with videos)
(A few more images available on the original page, including a USB version of the plug.)
I thought the most important aspect for us hifi guys here was demonstrated by the last three pics. So, thoughts?