The question is old and perhaps not specific enough to what I have in mind and what I hope to accomplish.
The best way to explain what I hope to do is by giving an example from an existing Wordpress site: http://flowingdata.com/
Now, the flowingdata blog can includes a couple of types of blog posts. Sometimes, a blog post will be a simple screenshot of another website's interesting visualization along with a description of the contents.
Here is a "normal" post:
When you examine the source for these "normal" posts, you can see all the wordpress-related baggage one expects to see in a normal wordpress blog post.
And then there can be a different, more specialized type of blog post(?) / article(?) / page(?), found often in the "Projects" section of the blog. (Important: not every "Project" post has the same custom format; e.g., some "Project" posts retain the blog's main navigation elements, and some "Project" posts eliminate the blog's main navigation.)
Custom "Project" post:
So my question is: if you were creating a Wordpress blog using an existing theme, what is the best, easiest, and most maintainable way to make custom pages similar to the ones one finds in the flowingdata blog?