Bear in mind that the databases have specific names, and that pretty
much describes what's in them. Your Content Databases will have all
your content, for instance. Your Config database has your
configuration, and so on. Like Mehmet said, there are a quite a few
things that end up in the 12 hive on your web servers that doesn't exist
in the databases and therefore wouldn't get recovered in a database only
recovery. I bet even in SPS if you attach to an existing config
database but don't have language templates or web parts installed pages
won't render. I know it's that way with WSS v2. Short answer, you're
better off than you were with v2/2003 but you still need more than just
the databases.