metadata panel comparison

Somewhat related to our work, a comparison of Apple's Aperture and  
Adobe's Lightroom metadata panels:

	<http://blog.duncandavidson.com/2006/09/aperture_vs_lig_1.html>

Adobe is using XMP internally for metadata, and Apple is now  
exporting it.

WRT to our requirements, the primary difference is that we'd allow  
more than just string properties, but references to other resource  
descriptions. In these screenshots, for example, a user should be  
able to select a copyright holder, or creator, or subject either  
using auto-complete or with a pop-up selector list.

In those cases, they would be stored as full resources with their own  
properties (name, address, email, etc.), even if in the panel their  
name was just displayed by default.

Bruce