I'm helping a friend with a project where he needs to have 3,000+ photos (and rising) organised. He's currently using iPhoto, which is great for him for keywording, rating and producing slideshows with captions. The limitation is that he needs to have a greater hierarchical structure, which iPhoto doesn't seem to do. i.e. he needs to have folders within folders. I can't seem to find the best option for him. Aperture may be an option as he could use the projects as a heading under which he could then use albums. This only gives him two levels though, and the editing functions are probably way more than he needs. I'm also not sure if the slideshows in Aperture an display captions. Any other suggestions? Thanks in advance!