>Used to be, and still am, a big fan of delimited strings, but with parameter passing in an OO world, I think it's less clear than manipulating properties or using an object. But, maybe the self-describing format of XML is the way to go!

There's a problem with XML; there's no pre-negotiated schema to pass processing instructions; (eg there's no pre-agreed p-code that I can use to pass a VB app the processing that goes on inside of a COM object or web service; as long as only data is being passed across by an object, there's no problem marshalling it with XML, but there are issue to at least negotiate in order to marshal behaviors.)