> In all of the XML vocabularies I've designed for clients, 
> standards and myself the last few years I've been avoiding:
> 
>    id=
> 
> in favour of:
> 
>    xml:id=
> 
> ref: http://www.w3.org/TR/2005/REC-xml-id-20050909/
> 
> because of the implied semantics.
> 
> I haven't run into any hiccoughs in any way by doing so ... 
> has anyone run into roadblocks or unintended consequences 
> doing the same?

I agree that's probably best practice nowadays. I don't think you can assume
that every combination of XML parser / XSLT processor will make xml:id
values accessible to the id() function, but then that's true for
DTD-declared ID attributes as well.

Michael Kay
http://www.saxonica.com/