This has come up a few times recently so I thought I would highlight a post from Todd Carter about how to get the x86 ASP.NET performance counters when running on an x64 OS:

http://blogs.msdn.com/toddca/archive/2007/05/08/logging-32bit-asp-net-performance-counters-on-a-windows-2003-64bit-os.aspx

Just thought I would call that posting out since it has been helpful.

The other day the topic came up about best practices with IIS and Hyper-V.  One of our team mates pointed out the following links which are an interesting read:

http://www.virtualization.info/2008/05/microsoft-migrates-msdn-and-technet-on.html

http://blogs.iis.net/mailant/archive/2008/05/29/technet-msdn-iis7-front-end-servers-running-100-virtualized-using-hyper-v.aspx

These go over the migration of MSDN/TechNet infrastructure over to Hyper-V.  Cool stuff!