Picasa

Picasa is a free organising and photo editing program by Google. It allows you to make Basic Fixes, Tune Light, and create Effects. For stuff you cannot do on Picasa, there is a link to Picnik.

Besides editing and organizing, Picasa allows you to email, print, rate, share, Geo-Tag, make collages, and even make slideshows.

Pictures are organized by folders, and can be found easily. Picasa also features face recognition, so you can verify groups of people.

Easter Egg
If you press ctrl + shift + y in the corresponding order, a teddy bear will pop up. If you continue to press those keys, the program soon is infested by them.