Microsoft released a new version of debugdiag, this live saving tool is a necessary tool for debugging web applications
IIS Download Center
There is a brand new download section at the IIS.net site.
Here you can download IIS related tools and add-ins.
Here is list of tools and links I use to troubleshoot problems on IIS boxes:
Filemon.exe (sysinternals tools)
Regmon.exe (sysinternals tools)
procexp.exe (sysinternals tools)
Logparser.exe (This is a super parser for IIS logs and much more. It’s a live/time saver)
IIS Debugtools (Debug Hangs/crashes memory leaks)
AuthDiag (Authentication problems)
IIS Resource Kit tools
IISTracer (Realtime monitoring)
google.com (of course)
Secure server passwords
This is a favorite link I use very often to generate complex passwords.
Hope you find it usefull.