I just switched back to a Mac after a hiatus with a Vista PC. I have all my photos organized into folders based on a very specific and personal organization system in which I am able to quickly find the original file for any of my 20,000 photos.
I'm already very annoyed by iPhoto's lack of support for a truly robust "referenced" file mode, since if you turn off the copy on import option, it actually really does still copy your photos the moment you make any changes, and deleting from iPhoto doesn't delete the original referenced file, etc.
The thing that is truly aggravating, that will likely make me never use iPhoto if there is no work around is that in regular (non-referenced) library mode, upon importing photos, it puts them all in these asininely named folders that are completely indistinguishable from each other. It's nice that in the GUI the photos are grouped by their original folder rather than by idiotic "events" that are otherwise arbitrarily created upon import from a camera, but when you want to go find the edited photo file to place on a thumb drive, or to upload through a dialog box on a website, or any other of the thousand tasks you're not able to do in iPhoto, you have to go searching through all these ridiculous folders.
Is there a way to change the naming conventions of these folders? Is it possible to make iPhoto store photos in file folders named based on the "Event" their contained in in the GUI? I might consider using iPhoto if there is some way to change this, because I do like a lot of the editing functions that are not in Picasa, and Picasa has built-in cross functionality with iPhoto libraries. Props to Google for ensuring interoperability, major negative points to Apple for making iPhoto into some kind of ivory tower.