He has recently gotten a lot of heat for some of his recent comments. But calling him a snake oil salesman hardly seems fitting, as he has heavily contributed to the AI field (in OCR, pattern recognition, and speech recognition if I recall correctly). Sure, the guy is a whack job (the stuff about medicine comes to mind), but he's one smart whack job.
John Underkoffler on gesture-based computing: http://www.ted.com/talks/view/id/872
Gary Flake on extreme data visualization: http://www.ted.com/talks/view/id/783
Jane McGonigal on how gamers can save the world: http://www.ted.com/talks/view/id/799
Stephen Wolfram on creating a computational theory of the universe: http://www.ted.com/talks/view/id/843
Pranav Mistry on a gesture-based interface that goes everywhere: http://www.ted.com/talks/view/id/685
Eric Topol on wireless tech in medicine: http://www.ted.com/talks/view/id/772
Tim Berners-Lee on making the world's data open source: http://www.ted.com/talks/view/id/788
Ray Kurzweil on machines that think and grow: http://www.ted.com/talks/view/id/560
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Edited to add: I just made a simple script to download the hi-res videos. Available here: http://bitbucket.org/johannes/tedget/wiki/Home
Then just run `./tedget 872 783 799 843 685 772 788 560`. (Please be nice with the good people at TED and only download what you need)