I think Guido's post on XML is a good occasion to point again to my rant about the disdain for XML among Python programmers, posted almost exactly a year ago on this blog.
I don't think Guido is right on the no XML in my template issue. I don't think he's wrong either. There are about as many ideas about what a templating language should be like as there are Python programmers, and Guido is, obviously, being a python programmer in this. Guido's rejection of XML for his own templating needs should not lead python programmers into believing that they can look at XML technologies in general with disdain.
Yes, XML is often misapplied. It has problems. That doesn't mean XML technologies are always useless, that they should never be considered in any software project, or that XML technologies can be safely ignored.