A few useful utilities:
Switch Window provides a handy little popup window that lists all current windows and you can easily switch between them. I tend to use the [Start] context menu to trigger it.
Microsoft XP PowerToys has a few tools that I use regularly, I’m just going to draw your attention to 2 of them below
I have the Alt-Tab Replacement installed so that when I do use alt+tab, I get a thumbnail of the open window, which helps me identify exactly which window I’m looking for. This is also a great tool for testing people’s powers of observation and seeing if they notice that your alt+tab is slightly more informative than theirs.
Command Prompt Here provides an extra context menu entry to open a command prompt set to the directory that you right clicked from in Explorer.
These tools give me a minor edge when I’m navigating Windows during the testing of Windows applications.