it's a great way for web developers/designers to become UI designers for .Net applications.
i had to create a UI in XSLT/XPATH that would be applied to raw XML data for use in a .Net application that was being written by a software developer.
It was actually a very smooth collaboration (in that little collaboration was required).
there are lots of resources out the, and some good firefox extensions that will take the headache out of trying to determine the XPATH of a given XML element.