Much as I like iPhoto in terms of functionality, I am worried about committing my photos to be managed by iPhoto in the long term. I feel much more confortable knowing that I can get at my photos via a plain file structure that I can move to and use on pretty much any file system that understands nested folders.
As I said, I just started using iPhoto with photos from our latest vacation. But I have a massive archive of photos that I collected over years. Those I have in a simple file organization (like several mentionned in this thread) - typically folder names reflect albums and events (in iPhoto parlance). I am very reluctant to commit all of those to iPhoto.
I have looked at other photo management systems (e.g Picasa) but they, like iPhoto, are too much of a black box. I have zero trust in Apple (or Google for that matter) to keep iPhoto over future versions, retaining full backwards compatibility and not breaking something that would make my old photos inaccessible. This is why I much prefer relying on my own organisation logic.
Don't get me wrong: I like the way iPhoto lets me organize my photos in events, albums, locations and people (via the face recognition mechanism). From what I understand, iPhoto provides a way that lets me use the best of both worlds, i.e. retain the originals of the photos in my own folder structure, and still record them in its own catalog with all the logical classifications in events, albums, etc.
I will try and explore that approach.
Albert