Digital Photos--How do you organize them?

I use Adobe's Lightroom. While a very good image editor, it also organizes your images. You can search by almost any EXIF data, add keywords, show photo locations on a map (providing you recorded GPS data when taking the image), Along with the Library, Develop, and Map functions, it has a Book (Blurb) Slideshow, Print & Web page generator.

I have over 100,000 images indexed, and can usually find what I'm looking for in seconds.