For this example I open up my Video folder and click Organize then Layout and select Preview Pane.

This opens up the Preview Pane in the left hand side of the window with a small player control for you to preview the video.  If you want you can even turn it into full screen from the preview.

The same is true for any audio files you want to preview as well.  Go into the music folder and set the same settings Organize then Layout and select Preview Pane.  Where you can use the simple player controls to listen to the file.

With picture files the same thing applies.  Just follow the steps we showed previously and you can review a larger thumbnail of each image in the preview pane.  Also notice on every preview be it a video or image file, there is plenty of additional information regarding the properties of the file in the area below.

Hopefully this helps folks who do not yet have Vista and are curious about what some of the new features are.  On the other hand if you are experienced with Vista and think the preview pane is an annoyance check out how to Disable Preview The Pane by The Geek!