Portal-based is a great way to go, and if our new portals package was stabilized with a good UI I'd actually suggest you guys think about taking that approach, Danielle. Converting Greenpeace's panels and story snippets into portlets would be quite easy because those things are implemented on your site with included templates - which is what the portal system does for you.
I'm planning to dive into cleaning up our portals stuff relatively soon, that's my plan at least ...
