If you have broadband access and you are passionate to learn from some of the World's leading and prominent scientist (according to the site), this is certainly a stimulating place to watch them share their ideas, experiences and knowledge (+1800 lectures). Yes, you can even find Noam Chomsky discussing Force, law and the prospects of survival. As for me, I prefer the Interviews section, where I can even enjoy watching an interview with Tim Berners-Lee, the inventor of the World Wide Web (WWW).
If you are hungry for lectures in the field of Computer Science (+500), you are going to love this site, though if your passion is in the areas of Environment, Science, Society , Arts, Business, Computers you might be disappointed (for now), as the lecture collections are quite limited.
Then again, I suppose the collections will continue to grow, so you never know :)