With the release of Windows 7, there are new keyboard shortcuts to learn (as I'm sure some actually came in Vista). One day I'll duplicate the shortcuts cheatsheet I had created for Windows XP, but in the mean time, here are a couple that I've started using.
Toggle through open windows
Most of us are familiar with Alt-Tab to toggle through your open windows, and Alt-Shift-Tab to toggle in reverse order. Some of us used an add-on to XP to display a thumbnail of the window as you toggle. With the familiar Alt-Tab in Windows 7 you now see thumbnails without the add-on. But if you want to see a bit more detail of what's contained within each window, try Windows key-Tab and Windows key-Shift-Tab to get a better view of the windows as you toggle through them.Set window position
Using the Windows key with the arrow buttons allows you to position the active window on the screen. This works great when you want to view two windows simultaneously. Click on the window you want on the left, then press Window key-Left arrow. Repeat if necessary until the window takes up the left side of the screen. Repeat with the window you want on the right and using the Right arrow button.