Writing for XML.com, Ronald Bourret has a nice roundup of how XML databases are gaining traction in large-scale applications. Ronald has been looking at XML repositories for a long-time, and maintains a very useful online resource on XML databases.
This is a drum we have been beating for some time now, of course. There is an important role for XML repositories, and we have written about this most recently in two white papers, one on component content management and one on the related W3C Standards.