I've recently decided that KeepVid is the YouTube-using teacher's best friend, at least in terms of not worrying about connectivity, firewalls, or ads at school. For instance these two videos are now on my hard drive ready to be used in my intro to earthquakes lesson next week:
On the other hand, I haven't figured out how to do anything but stream this one from google:
Do you have favorite tools for this that are different / better? If so, please share!