I have a site that I'm working on and I'm considering whether I should jump over to Drupal or continue with my home grown CMS.
The way my current system works is that the CMS and the site as essentially seperate, with the site being a client of the CMS. The site itself is not "integrated" with the CMS (for example, you can't go in to an Edit mode and click on a place on the site to change it). All content changes are done through the CMS.
The site is quite simple: several different "News" style pages, some basic static pages, etc.
The key component that I'm curious about, though, is that with the CMS, I can create new "templates" which consist of a list of properties. There are standard properties (like start and stop dates), and there are the extra properties (like Title, tag line, etc.). I can add as many properties as I like, I can add in place Images (as a property), etc. The properties are also typed (numbers, dates, strings, etc.).
As a CMS user, you select a story Category (Press Releases, Current Events), select a template based on that category, and then fill in the assorted fields. The site then gets that Story as a block of properties that it can place on the pages.