The first two years I took digital pictures, my meta data corrupted by the software that came with the camera. Because of this, I store the images from the first few years in folders named by who's in the picture.

Since 2003 I have kept my pictures in this structure:

{Year}
{Month}
{Day} (And any description)

For example, see folder from 2009 is as follows:

2009
12
02
05, Trip to Sweden
17, Circus school
20 visits to Uffe and Maj-Britt
24, Christmas Eve
27
28, In the zoo

How to store your images?