I just went to lunch with Leslie Dutton from Full Disclosure and shot a few promos for their series of video blogs -- which are really shaping up to be excellent. They get some of the biggest names in politics, especially in California, on camera and saying things they'll probably regret later.
Video blogging is still in its infancy, and won't be as easy as writing text until we have artificial intelligence software that can edit video automatically. Still, there are a few people out there producing great stuff that is often a lot more evokative than mere text. Evan Coyne Maloney may be the most famous; his videos are particularly entertaining, such as when he interviewed despondent Inaugeration protesters. Vidblogs.com bills itself as "the ultimate public voyer experiment" and links to hundreds of video bloggers. It's a fascinating niche, but I doubt that video will ever replace the written word, just as video phones have never really taken off.
Personally, it looks like too much work for me to get into. I'm lazy, and I already waste too much time writing nonsense; the last thing I need to do is spend hours filming and editing it. Plus, you can't "vlog" in your pajamas.