I'm cataloging old digital photos (those that I could rescue from my fading PowerBook).
I've always kept them in date-named directories as they are uploaded from the various cameras I've used (an older Olympus C-something80?, a Minolta S304 which was very nice, and now the Canon 300D) sometimes with a short phrase after the date indicating content or location or something that might be useful.
Since the images come out of the camera (all the cameras) with sequential names, I've often just left the images without descriptive names, figuring that if I'm looking for an image, I will probably remember roughly the shoot it came from and will therefore only have to look at one directory (or maybe a few). But I have sometimes put descriptive names on the images within the directories. This requires a certain inventiveness if I've taken more than one picture of a given subject, or the simple use of numbers to distinguish between dog pictures 0 - 18.
After checking out a number of photography sites, I liked this article the best, so I'm trying this method.
I use a utility (a demo version of PIE) to rename each directories worth of files with names of the form YYYYMMDD-###--descr.jpg, where YYYY is the year, MM the month, DD the day, ### a serial number, and I replace descr with my own short description. It's important to keep the entire string to 32 characters or less for purposes of writing to some media, I guess.
This way I can search (using nothing more than a directory lister) for files from a given year, month, or day (if I remember the day of a shoot) or by subject (all the photos of Kiernan, for instance).
Eventually it might make sense to put more information into a database, like filename plus a longer description. But it might not, too. The amount of extra work involved would be immense. I hope eventually to find a utility and printer combination that will create excellent proof sheets for me as well, so that I can keep a notebook of proofs in order to locate images.