I just figured this out by accident, but it's probably old news to most of you. If you hold the Apple Key, then push tab, it brings up all of your open apps in a transparent window. By pushing tab again, you can switch the app that's highlighted. When you release the apple button, the selected app comes to the foreground. This is a handy feature. Apple always goes above and beyond so mush that a year after switching I still find new features on a weekly basis!