Most of the TED talks are really interesting, and I tend to go through them every so often, but this one really stuck in my mind (maybe because of the focus on wealth in Africa later in the video and how financial and health aid for HIV should be specialised for regions, instead of pointing to the whoe continent as being needy).
JJ Abrams' talk on mystery is brilliant too.

The TED talks are now all podcast too which is great. Served on a plate.
This is a really awesome talk, I agree. Not only really interesting but shows how data is useless and information is not, and how turning one into the other has so much value. Also shows how good presenters are always passionate.