I'm really excited that Microsoft announced yesterday that IIS7 will now be a server role option as part of Windows Server 2008 (formerly known as longhorn) "server core". This means that you'll be able to install a minimalistic footprint for your server (i.e. without a gui shell) and run IIS7. In the past, it was deemed that IIS7 was too large to be put into server core due to its dependence on the .NET CLR, mainly because of the integrated pipeline with ASP.Net.
I'm still trying to figure out exactly what this means now that IIS7 will be part of server core, but I can tell you that I'm really excited that we've taken this step. Stay tuned for more info about this.