It would be nice if any technology that we promote for instructor use could also be readily used by students. In that regard, ooVoo only requires Webcam and headset so would seem to fit the bill. But if you want to post the recorded video, that requires fair amount of file space and a server. Students would use up their entire campus allocation with just a few movies, so they'd want some external host. Moreover, ooVoo produces the recording in .flv format. Although YouTube converts uploaded videos to .flv, it doesn't accept videos that are submitted in that format. However, blip.tv does! Further, blip.tv will render the video in the in original resolution rather than in a shrunken version. So for student use (or instructor use in Colleges that don't provide unlimited hosting), I'd recommend blip.tv
Do note that even blip doesn't accept .swf file format (Jing movies) so for that students would have to use some other Web space (sigh!) but those files tend to be smaller so their campus space should suffice.