Google has for some time now a service where you can upload videos and search and see videos uploaded by others (you can see it here). Recently they launched a video store as well, where they sell some TV series, NBA games, as well as videos which anybody can upload and request some money for others to see them. I think this will become a huge business in the future, but I don't intend to buy videos any time soon. As for the free ones, I found some funny ones, like commercials or some videoclips of Romanian bands that were off the copyright radar (they ban the videos for which the uploader does not have the copyright as soon as they find them).
What needs badly to be improved in order for this service to be usefull is the search. Currently it seems the search is done based only on the title of the video, which gives a rather poor results. I think an easy to implement idea would be to let users add keywords about a specific video. This can be abused by adding wrong keywords, but if most of the users are well behaved the resulting semantic should increase search quality.