Application Pool Manager (Free) at Harbar.net. Systematically recycles your application pools through a GUI.
PowerGui (Professional and Free versions available) at
www.powergui.org allows you to create and run PowerShell commandlets.
SharePoint Designer 2010 - 32-bit | 64-bit
SharePoint Manager 2007/2010 (Free) at CodePlex.com. A free tool that shows details of your entire MOSS farm.
VirtualBox (Free) at
VirtualBox.org: A free virtualization platform which allows a user to run either a 32- or 64-bit guest OS.
WSPBuilder (Free) at
CodePlex.com: A Free tool which allows a developer to package features into a .WSP that can be deployed quickly and without the fuss of modifying .XML or .DDF files. Has a Visual Studio plug-in or a command-line package.