Preferred tool for folding XML into HTML

[Russell Turpin]

This isn't really a Python question, but the Pythoneers are
smart folks, so I thought I would ask it here. Suppose a
development group is making a web app by using Python 
back-end scripts to generate XML. The XML is desired for 
automation and modularity. To create the interactive site, 
the problem then reduces to folding the dynamic data, as 
presented in XML, into static HTML pages. In other words,
the following translation is the last step in generating
each web page:

  XML (dynamic) + HTML template (static) -> final HTML

What are now the preferred tools for doing this?

Thanks!

Russell