For those fans of the Sysinternals utitilies by Mark Russinovich and Bryce Cogswell. You probably know that the suite of utilities was acquired by Microsoft earlier this year. The good news is that they are still free. Also you can now download the entire Suite (from here
)which is obviously much more convenient than downloading the tools individually.
It's really a collection of tools which a System admin might find useful. Most are command-line utilities although there are also some powerful GUI tools like Process Explorer which is a Task Manager replacement. Your best bet is to check out the tool descriptions on the site (Each tool has its own page)