TED.com is a web site of some excellent informative videos.
The talk Do Schools Kill Creativity? has been viewed on ted.com more than 41 million times and it is regarding creativity in education by Sir Ken Robinson. It is the most popular TED talk of all time.
Here is a link to the 20 most popular TED talks of all time.
One of my favourite talks is by Benjamin Zander at TED on appreciating classical music. Benjamin Zander has two infectious passions: classical music, and helping us all realize our untapped love for it.
Here is a terrific talk by Brene Brown on vulnerability called The Power of Vulnerability.
Hans Rosling gives a great talk using statistics and bubble charts on world life expectancy and fertility rates in his talk called The best stats you’ve ever seen. Hans Rosling gives a another great talk using statistics and data presentation in the talk Let my dataset change your mindset.