I have modified my header template to use the meta descriptions based on the page content. lots of MTIf tags are needed. If you are familiar with Movable Type Tags this will be easier for you.
Here is my new title, meta description and meta keyword tag from the header template in movable type.
<$MTGetVar name="page_title"$> - <$MTBlogName encode_html="1"$>
<$MTBlogName encode_html="1"$>
<$MTBlogName encode_html="1"$>: <$MTGetVar name="page_title"$>
This is a work in progress I am still experimenting on how i could optimize it and display meta keyword in the headers as well.
Thanks for writing a post on this. I am a huge believer in having custom meta data to support the content on individual pages. How has this worked for you? Have you been happy with the results?