I found this helpful post on another blog, called Just Plain Joy. In her post, the author (incidentally, her name matches mine) gives step-by-step instructions for her system of organizing her pictures on her hard drive. I recently sorted all my pictures in a similar manner, and have found it much more convenient!
The only problem with this system is that you have to know the approx. date that a picture is taken in order to find it on your computer. Does anyone have a solution to this problem? What kind of organizational system do you use?