IIS 7 works without much hassle with PHP applications and supports URL rewriting since about a year. There's now a real push by Microsoft to spread IIS 7 + fastcgi + PHP + urlrewrite with their new Webplatform installer.
IIS 7 is likely the most prevalent webserver on "wannabe" developer desktops (XP Pro, Vista Ultimate, Windows 7 XYZ) and, in my experience, much easier to configure (for newbies) than Apache.
We've been shipping Drupal with an Apache configuration file for a long time. Why not ship Drupal with a default web.config for IIS 7 to make Drupal even more accessible for new developers?
A side benefit would be to allow established .NET shops an easy entry point to use Drupal on their existing infrastructure.
A good web.config would
- make clean URLs work (big deal)
- make file protection work (big deal)
- make caching settings work
- make index.php the default document
- make index.php the 404 error handler
Preemptive:
But should we also ship with lighttpd configuration files? nginx? [favorite du jour]?
Maybe, but I do not think supporting IIS 7 means we need to cater to marginal servers as well.