Happy 10th Birthday XML.
It's clear you are going to be around for some time. People know your good points and bad and have got the kinks worked out using you in production, in diversity and at scale.
Take care not to be distracted in the next 10 years by sexy new text formats that overlap in some features, but don't replace you for many uses. I'm talking about you, JSON.
In the RDF world, RDF/XML is the syntax people love to hate, or just love/hate. It is 1 year younger than you, so maybe in February 2009 we'll have something to celebrate about that. Yeah, it might happen :)
I recently made a new textual RDF syntax sibling Turtle with TimBL whose official birthday was last month, although it's actual birth was January 2004 in Bristol, or earlier if you look into it's ancestry. In 6 (10?) more years it'll be something we can properly rely on, like XML is today.