Atomic Postel
My recommendation to application developers today is to use Atom 1.0, not RSS, as the basis for your content syndication.
You should absolutely continue to read and support RSS of all flavors. As Postel said, “be conservative in what you do; be liberal in what you accept from others.” In the context of content (or search) syndication, this may mean being able to read all sorts of formats, but only writing the one format that preserves the data the best. And today, I believe that format to be Atom 1.0.