When I rotate my iPod to the left, as two of the three iPods are in these examples, my volume buttons are on the bottom and my power button is on the lower left corner.
Look at the upright iPod in the top example. Note the location of the power button (on the top left corner) and volume buttons (left side). Now in your mind rotate it to the left. I wonder who's idea it was to use backwards mirrored images?!