Stratocam provides a random selection of some of the best images from Google earth.
Click on the left and right buttons to get a new image, or wait and let the site automatically cycle through them. Keep an eye on the URL, if you see one you like you can grab and hyperlink directly to that image. Or you could use the screen capture tools to grab an image and put it into your IWB software or PowerPoint.
This would make an excellent way to capture student interest at the start of a lesson by displaying some of these images as they enter the room. Geography teachers might also find some great images to use to support a lesson.
Take a look at www.stratocam.com