W.r.t. Sarah's post: I understand what she's saying and I share many of her thoughts. I would like to add what I wrote before: what does Google Apps and Sites imply for corporate Information Management?
What I do find, though, is that her post is written in a very defensive way, as if she is an IT department employee (as I am myself...). I miss a more opportunity-driven approach to your post. Of course Google sites isn't going to compete directly with Sharepoint, for now. But where could this take us anyway?