Hate to break it to you, but there is no one video to rule them all.
Now that that's out of the way, with intentional strategy you can have several great videos that suit your various needs and products.
We're talking:
Sales videos (check out our product!)
Tutorials (need to walk through some software?)
Promotional Videos
Launch Videos (psst, we've got a new product or service)
Manifesto Videos (perfect for non-profits)
Educational Videos
"Brandutainments" Videos (get to know our brand!)
and Social Media Videos