Chip I think your comment system swallowed my comment (no feedback after posting it) so I'll post it here.

Good work Chip! This is a really nice improvement.

There's an error though (looking at rev 3). The is_tax() conditional isn't true for category and tag archives as the diagram states. The "Taxonomy Archive" block should be removed, and the "Category Archive", "Tag Archive", and "Custom Taxonomy Archive" blocks should be moved up to the same level as "Date Archive", "Author Archive" and "Custom Post Type Archive".

Also the "Custom Post Type Archive" block can have "post-type-archive post-type-archive-$posttype" added for its body classes.

John