I understand your pain. I didn't move my old photos. It's just from now on, I use RawTherapee instead.
As far as file management goes (or DAM), the most elegant and future-proof solution is to store tags in the filesystem itself. Hence, no dependency on any particular software such as Aperture or LR. That's actually what OSX does: you can tag files with whatever keywords you like and search for files matching those. Only an indexer is required to index these tags and allow queries on them. Unfortunately, there is not good similar implementation in the GNU/Linux and Windows worlds.
As far as file management goes (or DAM), the most elegant and future-proof solution is to store tags in the filesystem itself. Hence, no dependency on any particular software such as Aperture or LR. That's actually what OSX does: you can tag files with whatever keywords you like and search for files matching those. Only an indexer is required to index these tags and allow queries on them. Unfortunately, there is not good similar implementation in the GNU/Linux and Windows worlds.