luba petrusha wrote:
I have some 50-100 libraries (haven't counted recently) which occupy most of my hard drive. I find it easiest to manage my photos with themed libraries (annual, trip, subject).
You could make each of your "themed Libraries" a Folder in Aperture, with all your current Projects and Albums intact. In this way, you could search across all of your Image at once (e.g.: a Smart Album showing all Images in which you've identified a Face as "Mom"; or filter for the keyword "Sunset"). In general, the more Images in a Library, the more useful that Library is. I strongly recommend one Library for each photographer (or group of photographers working as a business). Aperture has no trouble handling enormous Libraries (officially, it supports up to 1,000,000 Images, iirc).
A more advanced Library organization would replace each "themed" Folder+Projects with Albums. There is no reason to limit your "themes" to the Images in just the Projects contained in a Folder.
My general recommendation has always been to put all your Projects in one Folder (with sub-Folders as needed); and to put all your Albums in another top-level Folder. In this way you build two structures: a _storage_ structure, in which you put all your Projects, where each Project = one shoot, and an _access_ structure, where you have Albums organized by Folders into whatever groupings you need.
The newest version of Aperture (3.3.1) leans in this direction. For the first time there is a default division between Project storage and Album storage (one the Library tab of the Inspector, there are now two built-in top-level containers, one for Projects and one for Albums).
A separate issue is where on your system your Library and your Originals are stored. Aperture allows you to move your Originals to storage on external drives or other non-system drives. The limitation of the storage available on the system drive is something that all active photographers encounter at some point. (In Aperture-speak, you would convert Image's Originals from Managed to Referenced using "File➞Relocate Originals". This isn't something I'd look into right away, but rather after you become familiar with the Aperture interface.