TryIIS.com
If you have not try IIS 6.0, you have no ideas what you've missed :)
From TryIIS.com, 6 new reasons to try IIS 6.0
1) Best-in-class compression and consolidation capabilities that enrich and improve Web functionality with faster page downloads, support richer content, reduce costs, and improve server efficiency.
2) Rebuilt security from the code level up that reduces attack surface area and blocks most known types of Web attacks.
3) Reliable support you can depend on for tested solutions, training, and more.
4) Powered by Windows Server 2003.
5) A complete set of integrated application services that enable faster application development and reduce time-to-market for critically needed Web applications and services.
6) Best real-world platform as measured by both performance and total cost of ownership.