Tools for Assisting with Collection and Analyzing of Data for Problem Diagnosis

I was going through my Google Bookmarks and found a bunch of tools that are extremely helpful in diagnosing  many problems that occur on a web/app server and and interpreting the data collected. I’ve used all of them; they are all free and well known and used within the Community.  By no means is this an exhaustive list of all of the Tools and Add-Ins that I use - I'll get around to posting those someday : )

I’d start with the Data Collector. You can collect everything with Data Collector and then use the Log Parser and Visual Log Parser to help aggregate the data and even run queries against it. You may already know about some of these – but for those you haven’t seen, you should take a look!

Data Collector (supports IIS6 & IIS7, and can pull most other logs from any server):
http://blogs.msdn.com/b/carloc/archive/2010/02/01/idevdatacollector.aspx

Log Parser 2.2:
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=890cd06b-abf8-4c25-91b2-f8d975cf8c07&displaylang=en

Visual Log Parser:
http://visuallogparser.codeplex.com/

Log File Analysis:
http://blogs.msdn.com/b/delay/archive/2007/06/21/powerful-log-file-analysis-for-everyone-releasing-textanalysistool-net.aspx

Event Log Explorer:
http://www.eventlogxp.com/

IIS Log Analyzer (does graphs and reports):
http://www.iis.net/community/default.aspx?tabid=34&g=6&i=1864

IIS Diagnostics Toolkit (a suite of tools diagnosing Authentication, Authorization, SSL, Crash/Hang, etc.):
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=9bfa49bc-376b-4a54-95aa-73c9156706e7

and then of course the "big daddy" bunch of them all - Debugging Tools for Windows:
http://www.microsoft.com/whdc/devtools/debugging/default.mspx

I hope you find these useful : )