The PetaPixel site has compiled a list of  14 Powerful TED talks by Photographers, and as a fan of both TED talks and photography this seemed like a great resource.  Having taken a look at the list, I realise that I've already watched a few of them (and have even included a couple of them myself as blog posts before [1][2]) but there are still some there I haven't seen yet so I look forward to sitting back and watching them.