Who's used XSLT, XQuery, XPath or XPointer before?
I've personally tried them all and love how they operate! I was even considering creating an entire website in them about a year ago, but I think the technology is too new for older browsers to support them and so cross-compatibility becomes an issue which is nothing new. Worth looking into now though as I do believe they'll be a big part of the web-development industry in a few years.
The man who comes back through the Door in the Wall will never be quite the same as the man who went out.