Remember who Google loves the most. GOOGLE! By creating links within Google Buzz, Google Places, Google, Google, Google, you will be adding value to your sites seo. Obviously YouTube, owned by Google are great links.
If you want to learn how to use youtube effectively then you should check out the YouTube Traffic System
I've never had very much success with Youtube. Suffice to say that you have to have a video that's actually worthwhile (not just a blatant advertisement) that people will actually share, enjoy, and comment on. There's no quick and easy way to do it; you're forced to be completely whitehat.
I guess every good ideas has been covered already in the conversation. But YouTube is a more expressive channel than any other channel because visuals create more impact than text. In the end its all about a good strategy.