Now it would be possible to just copy all photos to my LAN server with a few terabytes and Gigabit ethernet, but that would make looking through and at the photos terribly inconvenient.
Even worse, parts of my photos were imported as RAW and iPhoto was doing its own magic to convert them to JPEG.
iPhoto was not bad a bad program, I actually liked it, but relying on it was a lesson for me to never again store my photos in a closed-source program.
Currently I'm still looking for alternatives, Lychee (http://lychee.electerious.com/) looks nice at first sight, but I don't want a PHP server with MySQL managing my photos.
IMO the nicest solution would be a well-defined photo directory format that gets indexed by a fast server implementing an API that you can use to access all photos through client programs. It could keep an SQLite database in the directory to store metadata, but if it is gone, the directories should still make sense.