"Windows Internals and Advanced Troubleshooting" training
Later this year, SysInternals/WinInternals founder Mark Russinovich and David Solomon are offering a top-notch class on troubleshooting that covers current OS versions as well as upcoming changes to the OS in Vista (next Windows version)
http://www.sysinternals.com/Troubleshooting.html
This class appears to be similar to the PDC05 precon session some of us went to last fall, except it is 5-days instead of a 5-hours! If you want to understand Windows to the Nth degree, this is definitely the class.