The third image would have been a bit more challenging if I had been using the in-camera meter, which only measures the light reflected off the subject. Because she was relatively pale, but standing against a wall that was painted black, I likely would have ended up with an overexposed image. By measuring the light falling on her, rather than reflecting from her, I was able to get a more accurate idea of what the proper exposure time should be. On brighter days, you have to be careful not to hold the meter in your own shadow, as this can affect your measurements and result in an overexposed image.
When shooting with digital you need to be meticulously accurate with your light readings. Unlike film, which has a wider latitude when it comes to your exposure, digital (especially JPEGs) requires you to be spot on. What looks good on the finder may be, in reality, wildly overexposed on your computer screen. A handheld meter isn't always practical, especially in high-impact scenes, but for photos where you need your exposure right on target, nothing beats having one on hand.