I think video web marketing is the future. It gives the viewer a more respectable outlook of the product offer and shows that the site owner is an expert and an authority in the subject. With all of the marketing clutter going on it seems that business owners who are different and stand out from the crowd get the best results.
Here's a good example of what I would call a well done video marketing website. It has all the elements together, video, content, bullets, social proof, opt-in etc...
Authority Black Book - Social Marketing Tactics and Web 2.0 Traffic Generation Strategies...
Not to mention it is a free book which would greatly increase opt-in subscribe rates. I like how the video draws you in to take action. I would think this example is an effective way to use video marketing on a sales page.