There's been so many technologies for me to learn since joing Microsoft. IIS7 is one that I had not seen yet and it is truely impressive. The Metabase is DEAD! You can now configure IIS7 websites using the web.config file which means application deployment and configuration is a lot easier.
One of the things you can configure is the modules that are configured for each site. You can not only add your own modules, but you can remove modules provided by Microsoft. One of the demos I saw showed all of the modules removed including authentication and static file modules. Basically, configured a null web server. The advantage of this is total control over what bits are running on the server.
Another feature of file-based configuration is that site managers can configure their website without having to be administrator on the server machine.
There were a ton of features shown..too many to write about. I'll point you to the Communications track at PDC Bloggers for observations from others.