RE: application/xml vs text/xml

> The IANA content type categorizations have never been particularly
> usefull wrt text. According to the rules html should have been 
> application/html since it is not ascii text...

There was never a requirement that text/* be ASCII. On the other hand,
'application/html' is more appropriate for HTML 4.0, because HTML
now includes script tags and other processing elements that are not
merely text and its annotations but program.
I would favor the registration of application/html, however. Let's
not compound the error by making it again.

> I would recommend text/xml since if the DTD is declared a generic
> xml text viewer could well make a decent job at presenting the
> content and in general XML is aimed as a text markup language..

This is not a good argument; you could configure your system to view
application/xml as well as text/xml. It's more of an issue of security
considerations.