TED, besides producing their own great speeches, also offers a curated "best of the web". Today's presentation, in honour of the open launch of Pottermore, is J.K. Rowling's commencement speech at Harvard in 2008 on the fringe benefits of failure.
It regularly makes top lists of inspiring speeches. Have a watch and enjoy! (And if you'd prefer to watch it in a slightly larger window, here's a direct link, too.