I love TEDTalks. You get to listen to some great ideas (and performances) from brilliant people.

TED has digitised its archives so presentations from as far back as 1984 are now available. One of the first is Nicholas Negroponte's talk from 1984. Negroponte was in charge of the MIT Media Labs. Many of his predictions made in this presentation have come true.

Check here for the list of all the talks. You can select by a number of characteristics.