What Form Does Your Message Take?
I have to agree with most of what Alec said in his post on the subject of having a video blog, though I have a different take on the matter.
What it boils down to for me is that I have a face for radio and a voice for the written word. I generally express myself far better in written words than I can do either speaking or in person. Instead of trying to make myself do something I'm not as good at, I go with my strength, which is my writing.
I also think that you should use the medium most appropriate for the message you are trying to deliver. Most of what I am saying can be delivered in writing effectively. I've done audio and I've done video, but only when it is an appropriate medium to deliver the message or it is a more efficient medium of delivery (for example, the multiparty conversations we have on the VoIP Think Tank podcast).